diff --git a/.Rbuildignore b/.Rbuildignore
index fd19815..d77493b 100644
--- a/.Rbuildignore
+++ b/.Rbuildignore
@@ -13,5 +13,3 @@
 ^\.vscode$
 ^\.claude$
 ^CLAUDE.md$
-^w-build$
-^w-install$
diff --git a/.github/workflows/R-CMD-check.yaml b/.github/workflows/R-CMD-check.yaml
index e783e01..17b0fba 100644
--- a/.github/workflows/R-CMD-check.yaml
+++ b/.github/workflows/R-CMD-check.yaml
@@ -21,12 +21,11 @@ jobs:
         config:
           - {os: ubuntu-24.04-arm, r: 'devel', http-user-agent: 'release'}
           - {os: ubuntu-latest,    r: 'release'}
-          - {os: ubuntu-latest,    r: 'oldrel-1'}
           - {os: ubuntu-22.04,     r: 'oldrel-3'}
           - {os: macOS-latest,     r: 'release'}
           - {os: macos-15-intel,   r: 'oldrel-2'}
           - {os: windows-latest,   r: 'release'}
-          - {os: windows-latest,   r: 'oldrel-4'}
+          - {os: windows-latest,   r: 'oldrel-5'}
 
     env:
       GITHUB_PAT: ${{ secrets.GITHUB_TOKEN }}
diff --git a/.gitignore b/.gitignore
index 0cdc162..7a286c3 100644
--- a/.gitignore
+++ b/.gitignore
@@ -2,8 +2,6 @@
 .Rhistory
 .RData
 .Ruserdata
-/w-build/
-/w-install/
 /docs/
 /revdep/
 /.claude/
diff --git a/CLAUDE.md b/CLAUDE.md
index 6020b64..70e6575 100644
--- a/CLAUDE.md
+++ b/CLAUDE.md
@@ -74,17 +74,51 @@ The package uses GitHub Actions workflows in `.github/workflows/`:
 
 ### Build System
 
-**Configure Scripts:**
-- `configure` (Linux/macOS): Detects system-installed libfswatch in standard locations (`/usr/local`, `/usr`, homebrew paths). If not found, compiles bundled libfswatch (v1.19.0-dev) using cmake. Handles special cases like ARM atomic operations.
-- `configure.win` (Windows non-UCRT): Compiles libfswatch from source for both x64 and i386 architectures
-- `configure.ucrt` (Windows UCRT): Simplified version for modern Windows R builds
-- All scripts generate `src/Makevars` with appropriate compiler flags
-
-**Key Dependencies:**
-- libfswatch (bundled source in `src/fswatch/`)
-- cmake (required for compiling libfswatch from source)
-- pthread (for background monitoring thread)
-- 'later' R package (for async callback execution)
+The bundled libfswatch sources (`src/fswatch/`) are compiled **directly into the
+package shared object** alongside `init.c`/`watcher.c` — no cmake, no static
+archive, no separate library. Platform feature selection comes from a
+hand-maintained config header, not host probing.
+
+**Configure scripts:**
+- `configure` (Linux/macOS/other Unix): detects a system libfswatch
+  (`/usr/local`, `/usr`, Homebrew); if absent, sets up the in-place bundled
+  build. Probes for `-latomic` (ARM) and adds `-framework CoreServices` (macOS),
+  emits the `CXX_STD` line (only on R < 4.3), and substitutes `src/Makevars.in`
+  → `src/Makevars`.
+- `configure.ucrt` (Windows UCRT): computes only the `CXX_STD` line,
+  substituting `src/Makevars.ucrt.in` → `src/Makevars.ucrt`.
+- Legacy non-UCRT Windows has no `configure.win`; it uses the static
+  `src/Makevars.win`, and `Biarch: true` keeps the dual i386/x64 build.
+
+**Key pieces:**
+- `src/fswatch/.../libfswatch_config.h`: hand-maintained; selects `HAVE_*`
+  features from compiler platform macros (replaces the cmake/autotools probe).
+- `src/Makevars{.in,.win,.ucrt.in}`: declare the bundled objects and carry one
+  portable explicit compile rule per object (no GNU-make extensions). The POSIX
+  object list is `tools/fsw_objects_posix.list`; the Windows object list is
+  separate because those files include `<windows.h>`.
+- `src/link.cpp`: empty `.cpp` that forces R to link with the C++ linker.
+- `tools/update_libfswatch.sh`: re-vendors libfswatch and regenerates the config
+  header, object list, and Makevars; calls `tools/patch_libfswatch.sh`.
+- `tools/patch_libfswatch.sh`: idempotent source patches — a null-format guard
+  in `string_utils`, self-guards on the fsevents/inotify/fanotify monitors, and
+  neutering of libfswatch's stdout/stderr/cerr logging (for the R CMD check
+  "compiled code" policy).
+
+**Key dependencies:** an R C/C++ toolchain plus `make`; pthread; the
+'later' R package. A system libfswatch is used automatically when present.
+
+### C++ Standard and Minimum R Version
+
+The bundled libfswatch uses `std::filesystem` (in `path_utils`, `poll_monitor`,
+and every monitor's `scan()`), which mandates **C++17** — there is no portable
+pre-C++17 substitute. Because the package now compiles libfswatch itself rather
+than via cmake, it relies on R's own `CXX_STD = CXX17`, support for which was
+added in **R 3.5.0**. That is precisely why `DESCRIPTION` requires
+`R (>= 3.5)`: it is the lowest R that can build the package (R < 3.5 cannot
+request C++17), not an arbitrary floor. `configure`/`configure.ucrt` emit
+`CXX_STD = CXX17` only on R < 4.3, since R >= 4.3 defaults to C++17 and
+specifying it then trips a CRAN "drop specification unless essential" NOTE.
 
 ### Event Filtering
 
@@ -102,12 +136,13 @@ The package filters filesystem events to only report main event types (Created,
 ### Windows
 - Uses ReadDirectoryChangesW API (always recursive)
 - Windows latency has been specifically addressed (see NEWS.md - patch in v0.1.4.9000)
-- Builds require cmake and compile libfswatch from bundled source
+- Compiles the bundled libfswatch in place: UCRT via `Makevars.ucrt` (generated
+  by `configure.ucrt`), legacy non-UCRT via the static `Makevars.win` (gcc 8.3
+  needs `-lstdc++fs` for `std::filesystem`); `Biarch: true` builds i386 + x64
 
 ### macOS
 - Uses FSEvents API (always recursive)
-- Can use system libfswatch if installed via homebrew/MacPorts
-- MACOSX_DEPLOYMENT_TARGET is automatically extracted from compiler flags
+- Links `-framework CoreServices`; can use a system libfswatch (Homebrew/MacPorts)
 
 ### Linux
 - Uses inotify API
diff --git a/DESCRIPTION b/DESCRIPTION
index 048b09d..5a5ee2e 100644
--- a/DESCRIPTION
+++ b/DESCRIPTION
@@ -34,5 +34,5 @@ Config/roxygen2/version: 8.0.0
 Config/testthat/edition: 3
 Config/usethis/last-upkeep: 2025-04-23
 Encoding: UTF-8
-SystemRequirements: 'libfswatch', or 'cmake' to compile from package
-    sources
+SystemRequirements: 'libfswatch' (optional, bundled copy compiled
+    otherwise)
diff --git a/NEWS.md b/NEWS.md
index 6ae5fe2..9db5967 100644
--- a/NEWS.md
+++ b/NEWS.md
@@ -1,5 +1,8 @@
 # watcher (development version)
 
+* Building the bundled 'libfswatch' from source no longer requires 'cmake', now directly using the R C/C++ toolchain.
+  A system 'libfswatch' is still used when one is available.
+
 # watcher 0.1.6
 
 * Updates bundled 'libfswatch' source to 1.20.1 release.
diff --git a/README.Rmd b/README.Rmd
index b3a65da..dd83edf 100644
--- a/README.Rmd
+++ b/README.Rmd
@@ -53,7 +53,6 @@ watcher requires the 'libfswatch' library.
 
 - On Linux / MacOS, an installed version will be used if found in the standard filesystem locations.
 - On Windows, or if not found, the bundled version of 'libfswatch' 1.20.1 will be compiled from source.
-- Source compilation of the library requires 'cmake'.
 
 ## Quick Start
 
diff --git a/README.md b/README.md
index b841cdc..90c2564 100644
--- a/README.md
+++ b/README.md
@@ -49,7 +49,6 @@ watcher requires the ‘libfswatch’ library.
   standard filesystem locations.
 - On Windows, or if not found, the bundled version of ‘libfswatch’
   1.20.1 will be compiled from source.
-- Source compilation of the library requires ‘cmake’.
 
 ## Quick Start
 
diff --git a/cleanup b/cleanup
index abb582c..a0633de 100755
--- a/cleanup
+++ b/cleanup
@@ -1,2 +1,3 @@
 #!/bin/sh
-rm -rf src/Makevars w-build w-install
+rm -f src/Makevars src/*.so
+find src -name '*.o' -delete 2>/dev/null
diff --git a/cleanup.win b/cleanup.win
index 9c75dc1..6bab7a1 100755
--- a/cleanup.win
+++ b/cleanup.win
@@ -1 +1,2 @@
-rm -rf src/Makevars w-build w-install
+rm -f src/Makevars src/Makevars.ucrt src/*.dll
+find src -name '*.o' -delete 2>/dev/null
diff --git a/codecov.yml b/codecov.yml
index 04c5585..bf2a76c 100644
--- a/codecov.yml
+++ b/codecov.yml
@@ -12,3 +12,5 @@ coverage:
         target: auto
         threshold: 1%
         informational: true
+ignore:
+  - "src/fswatch"
diff --git a/configure b/configure
index dda384a..1a8a350 100755
--- a/configure
+++ b/configure
@@ -1,22 +1,8 @@
 #!/bin/sh
 
 # Initialise
-PKG_CFLAGS=""
 PKG_LIBS="-lpthread"
 
-# Helper function: detect cmake
-detect_cmake() {
-  if which cmake > /dev/null 2>&1; then
-    return 0
-  fi
-  export PATH=$PATH:/Applications/CMake.app/Contents/bin
-  if which cmake > /dev/null 2>&1; then
-    return 0
-  fi
-  echo "Required 'cmake' not found"
-  exit 1
-}
-
 # Helper function: find library paths
 # Usage: find_lib_paths <lib_name> <header_subdir> <default_libs>
 # Sets: LIB_CFLAGS, LIB_LIBS
@@ -51,9 +37,11 @@ CPPFLAGS=`"${R_HOME}/bin/R" CMD config CPPFLAGS`
 LDFLAGS=`"${R_HOME}/bin/R" CMD config LDFLAGS`
 export CC CFLAGS CPPFLAGS LDFLAGS
 
-if [ -z "$MACOSX_DEPLOYMENT_TARGET" ]; then
-  export MACOSX_DEPLOYMENT_TARGET=`echo $CC | sed -En 's/.*-version-min=([0-9][0-9.]*).*/\1/p'`
-fi
+# C++ standard: the bundled libfswatch requires C++17. R >= 4.3 compiles C++ as
+# C++17 by default, so requesting it explicitly is redundant and trips a CRAN
+# "please drop specification unless essential" NOTE. Only emit CXX_STD on older
+# R, where the default is below C++17.
+CXX_STD_LINE=`"${R_HOME}/bin/Rscript" -e 'cat(if (getRversion() < "4.3.0") "CXX_STD = CXX17" else "")'`
 
 # Detect -latomic linker flag for ARM architectures (Raspberry Pi etc.)
 echo "#include <stdint.h>
@@ -66,14 +54,14 @@ if [ $? -ne 0 ]; then
   PKG_LIBS="$PKG_LIBS -latomic"
 fi
 
-# Determine whether to compile bundled library
+# Determine whether to compile the bundled library
 compile_fswatch=0
 
 if [ -n "$WATCHER_LIBS" ]; then
   echo "WATCHER_LIBS is set... building from source"
   compile_fswatch=1
 else
-  # Find libfswatch
+  # Find a system libfswatch
   find_lib_paths "fswatch" "libfswatch" "-lfswatch"
   FSWATCH_CFLAGS="$LIB_CFLAGS"
   FSWATCH_LIBS="$LIB_LIBS"
@@ -88,36 +76,37 @@ int main() {
     compile_fswatch=1
   else
     echo "Found 'libfswatch' $FSWATCH_CFLAGS"
-    PKG_CFLAGS="$FSWATCH_CFLAGS $PKG_CFLAGS"
     PKG_LIBS="$FSWATCH_LIBS $PKG_LIBS"
   fi
 fi
 
-# Compile libfswatch if needed
-if [ $compile_fswatch -eq 1 ]; then
-  echo "Compiling 'libfswatch' from source ..."
-  detect_cmake
-  cmake -S src/fswatch -B w-build \
-    -DCMAKE_INSTALL_PREFIX=w-install \
-    -DCMAKE_INSTALL_LIBDIR=lib \
-    -DCMAKE_BUILD_TYPE=Release \
-    -DCMAKE_POSITION_INDEPENDENT_CODE=1 \
-    -DCMAKE_COLOR_MAKEFILE=0 \
-    -DCMAKE_INSTALL_MESSAGE=NEVER \
-    -DBUILD_LIBS_ONLY=1 \
-    -DUSE_NLS=0
-  cmake --build w-build --target install
-  rm -rf w-build
-fi
-
-# Set flags for bundled library
-if [ -d "w-install/lib" ]; then
-  PKG_CFLAGS="-I../w-install/include $PKG_CFLAGS"
-  PKG_LIBS="../w-install/lib/libfswatch.a $PKG_LIBS"
+if [ "$compile_fswatch" -eq 1 ]; then
+  # Compile the bundled libfswatch in place: put its source tree on the include
+  # path and build the POSIX object list (common core + the self-guarding POSIX
+  # monitors). The monitors self-guard on platform macros, so no uname-based
+  # source selection is needed.
+  echo "Compiling bundled 'libfswatch' in place ..."
+  PKG_CPPFLAGS="-Ifswatch/libfswatch/src"
+  # Single whitespace-separated line: embedded newlines would terminate the make
+  # variable assignment.
+  FSW_OBJECTS=`tr '\n' ' ' < tools/fsw_objects_posix.list | sed 's/ *$//'`
+  case `uname -s` in
+    Darwin) PKG_LIBS="$PKG_LIBS -framework CoreServices" ;;
+  esac
+else
+  # System libfswatch: compile against ITS headers only. The bundled tree is
+  # deliberately kept off the include path so the package compiles against the
+  # same libfswatch version it links. No bundled objects are built.
+  PKG_CPPFLAGS="$FSWATCH_CFLAGS"
+  FSW_OBJECTS=""
 fi
 
 # Write to Makevars
-sed -e "s|@cflags@|$PKG_CFLAGS|" -e "s|@libs@|$PKG_LIBS|" src/Makevars.in > src/Makevars
+sed -e "s|@cppflags@|$PKG_CPPFLAGS|" \
+    -e "s|@libs@|$PKG_LIBS|" \
+    -e "s|@fsw_objects@|$FSW_OBJECTS|" \
+    -e "s|@cxx_std@|$CXX_STD_LINE|" \
+    src/Makevars.in > src/Makevars
 
 # Success
 exit 0
diff --git a/configure.ucrt b/configure.ucrt
index 89cbfca..cddf6ee 100755
--- a/configure.ucrt
+++ b/configure.ucrt
@@ -1,22 +1,15 @@
-# Find compiler and export flags
-CC=`"${R_HOME}/bin/R" CMD config CC`
-CFLAGS=`"${R_HOME}/bin/R" CMD config CFLAGS`
-CPPFLAGS=`"${R_HOME}/bin/R" CMD config CPPFLAGS`
-LDFLAGS=`"${R_HOME}/bin/R" CMD config LDFLAGS`
-export CC CFLAGS CPPFLAGS LDFLAGS
+#!/bin/sh
 
-echo "Compiling 'libfswatch' from source ..."
-cmake -S src/fswatch -B w-build -G "Unix Makefiles" \
-  -DCMAKE_INSTALL_PREFIX=w-install \
-  -DCMAKE_INSTALL_LIBDIR=lib \
-  -DCMAKE_BUILD_TYPE=Release \
-  -DCMAKE_POSITION_INDEPENDENT_CODE=1 \
-  -DCMAKE_COLOR_MAKEFILE=0 \
-  -DCMAKE_INSTALL_MESSAGE=NEVER \
-  -DBUILD_LIBS_ONLY=1 \
-  -DUSE_NLS=0
-cmake --build w-build --target install
-rm -rf w-build
+# UCRT (Rtools42+) configure: the only thing to compute on Windows is the C++
+# standard request. R >= 4.3 compiles C++ as C++17 by default, so specifying
+# CXX_STD = CXX17 explicitly trips a CRAN "please drop specification unless
+# essential" NOTE. Emit CXX_STD only on older R (R 4.2), where the default is
+# below the C++17 that the bundled libfswatch needs. Everything else in
+# Makevars.ucrt is static (legacy Makevars.win stays fully static -- Rtools40
+# only ever serves R <= 4.1).
+
+CXX_STD_LINE=`"${R_HOME}/bin/Rscript" -e 'cat(if (getRversion() < "4.3.0") "CXX_STD = CXX17" else "")'`
+
+sed -e "s|@cxx_std@|$CXX_STD_LINE|" src/Makevars.ucrt.in > src/Makevars.ucrt
 
-# Success
 exit 0
diff --git a/configure.win b/configure.win
deleted file mode 100755
index 12ac227..0000000
--- a/configure.win
+++ /dev/null
@@ -1,30 +0,0 @@
-for ARCH in x64 i386; do
-
-  if [ -e "${R_HOME}/bin/${ARCH}/R" ]; then
-    CC=`"${R_HOME}/bin/${ARCH}/R" CMD config CC`
-    CFLAGS=`"${R_HOME}/bin/${ARCH}/R" CMD config CFLAGS`
-    CPPFLAGS=`"${R_HOME}/bin/${ARCH}/R" CMD config CPPFLAGS`
-    LDFLAGS=`"${R_HOME}/bin/${ARCH}/R" CMD config LDFLAGS`
-    export CC CFLAGS CPPFLAGS LDFLAGS
-
-    echo "Compiling 'libfswatch' from source for ${ARCH} ..."
-    cmake -S src/fswatch -B w-build -G "Unix Makefiles" \
-      -DCMAKE_INSTALL_PREFIX=w-install/${ARCH} \
-      -DCMAKE_INSTALL_LIBDIR=lib \
-      -DCMAKE_BUILD_TYPE=Release \
-      -DCMAKE_POSITION_INDEPENDENT_CODE=1 \
-      -DCMAKE_COLOR_MAKEFILE=0 \
-      -DCMAKE_INSTALL_MESSAGE=NEVER \
-      -DBUILD_LIBS_ONLY=1 \
-      -DUSE_NLS=0
-    cmake --build w-build --target install
-    rm -rf w-build
-
-  else
-  echo "Note: ${ARCH} not installed, skipping ..."
-  fi
-
-done
-
-# Success
-exit 0
diff --git a/src/.gitignore b/src/.gitignore
index e838631..0f6c845 100644
--- a/src/.gitignore
+++ b/src/.gitignore
@@ -2,3 +2,4 @@
 *.so
 *.dll
 Makevars
+Makevars.ucrt
diff --git a/src/Makevars.in b/src/Makevars.in
index 7530c82..2c9d70f 100644
--- a/src/Makevars.in
+++ b/src/Makevars.in
@@ -1,17 +1,73 @@
-PKG_CFLAGS = @cflags@ $(C_VISIBILITY)
+# Generated by tools/update_libfswatch.sh -- do not edit by hand.
+#
+# Compile the bundled libfswatch sources directly into the package shared object
+# (no cmake, no static archive). configure substitutes the include flags, the
+# link flags, the bundled object list (empty when a system libfswatch is used)
+# and the C++ standard line (a CXX_STD request set only on R < 4.3 -- see
+# configure).
+#
+# PKG_CPPFLAGS carries the include path so it reaches BOTH the C package files
+# and the bundled C++ via $(ALL_CPPFLAGS).
+PKG_CPPFLAGS = @cppflags@
+PKG_CFLAGS = $(C_VISIBILITY)
+PKG_CXXFLAGS = $(CXX_VISIBILITY)
 PKG_LIBS = @libs@
 
-SOURCES = init.c watcher.c
-OBJECTS = $(SOURCES:.c=.o)
+@cxx_std@
 
-.PHONY: all cleanup clean
+# Top-level package sources (built by R's own suffix rules)
+P_OBJECTS = init.o watcher.o
+# Bundled libfswatch objects (empty when a system libfswatch is used)
+FSW_OBJECTS = @fsw_objects@
 
-all: cleanup
+OBJECTS = $(P_OBJECTS) $(FSW_OBJECTS)
 
-cleanup: $(SHLIB)
-	@rm -rf ../w-install
+FSW = fswatch/libfswatch/src/libfswatch
+
+# `all:` MUST be the first target: an explicit object rule below would otherwise
+# become make's default goal when R CMD SHLIB invokes make with no target.
+all: $(SHLIB)
 
 $(SHLIB): $(OBJECTS)
 
+# --- Explicit compile rules for the bundled (subdirectory) sources -----------
+# One rule per object; recipe identical to R's own .cpp.o suffix rule. Each
+# names its source explicitly and uses only portable make variables, so any
+# POSIX make builds them (no automatic-variable source refs, no pattern rules,
+# no directory search, no file inclusion).
+$(FSW)/c/cevent.o: $(FSW)/c/cevent.cpp
+	$(CXX) $(ALL_CPPFLAGS) $(ALL_CXXFLAGS) -c $(FSW)/c/cevent.cpp -o $@
+$(FSW)/c/libfswatch.o: $(FSW)/c/libfswatch.cpp
+	$(CXX) $(ALL_CPPFLAGS) $(ALL_CXXFLAGS) -c $(FSW)/c/libfswatch.cpp -o $@
+$(FSW)/c/libfswatch_log.o: $(FSW)/c/libfswatch_log.cpp
+	$(CXX) $(ALL_CPPFLAGS) $(ALL_CXXFLAGS) -c $(FSW)/c/libfswatch_log.cpp -o $@
+$(FSW)/c++/event.o: $(FSW)/c++/event.cpp
+	$(CXX) $(ALL_CPPFLAGS) $(ALL_CXXFLAGS) -c $(FSW)/c++/event.cpp -o $@
+$(FSW)/c++/filter.o: $(FSW)/c++/filter.cpp
+	$(CXX) $(ALL_CPPFLAGS) $(ALL_CXXFLAGS) -c $(FSW)/c++/filter.cpp -o $@
+$(FSW)/c++/libfswatch_exception.o: $(FSW)/c++/libfswatch_exception.cpp
+	$(CXX) $(ALL_CPPFLAGS) $(ALL_CXXFLAGS) -c $(FSW)/c++/libfswatch_exception.cpp -o $@
+$(FSW)/c++/monitor.o: $(FSW)/c++/monitor.cpp
+	$(CXX) $(ALL_CPPFLAGS) $(ALL_CXXFLAGS) -c $(FSW)/c++/monitor.cpp -o $@
+$(FSW)/c++/monitor_factory.o: $(FSW)/c++/monitor_factory.cpp
+	$(CXX) $(ALL_CPPFLAGS) $(ALL_CXXFLAGS) -c $(FSW)/c++/monitor_factory.cpp -o $@
+$(FSW)/c++/path_utils.o: $(FSW)/c++/path_utils.cpp
+	$(CXX) $(ALL_CPPFLAGS) $(ALL_CXXFLAGS) -c $(FSW)/c++/path_utils.cpp -o $@
+$(FSW)/c++/poll_monitor.o: $(FSW)/c++/poll_monitor.cpp
+	$(CXX) $(ALL_CPPFLAGS) $(ALL_CXXFLAGS) -c $(FSW)/c++/poll_monitor.cpp -o $@
+$(FSW)/c++/string/string_utils.o: $(FSW)/c++/string/string_utils.cpp
+	$(CXX) $(ALL_CPPFLAGS) $(ALL_CXXFLAGS) -c $(FSW)/c++/string/string_utils.cpp -o $@
+$(FSW)/c++/fsevents_monitor.o: $(FSW)/c++/fsevents_monitor.cpp
+	$(CXX) $(ALL_CPPFLAGS) $(ALL_CXXFLAGS) -c $(FSW)/c++/fsevents_monitor.cpp -o $@
+$(FSW)/c++/kqueue_monitor.o: $(FSW)/c++/kqueue_monitor.cpp
+	$(CXX) $(ALL_CPPFLAGS) $(ALL_CXXFLAGS) -c $(FSW)/c++/kqueue_monitor.cpp -o $@
+$(FSW)/c++/inotify_monitor.o: $(FSW)/c++/inotify_monitor.cpp
+	$(CXX) $(ALL_CPPFLAGS) $(ALL_CXXFLAGS) -c $(FSW)/c++/inotify_monitor.cpp -o $@
+$(FSW)/c++/fanotify_monitor.o: $(FSW)/c++/fanotify_monitor.cpp
+	$(CXX) $(ALL_CPPFLAGS) $(ALL_CXXFLAGS) -c $(FSW)/c++/fanotify_monitor.cpp -o $@
+$(FSW)/c++/fen_monitor.o: $(FSW)/c++/fen_monitor.cpp
+	$(CXX) $(ALL_CPPFLAGS) $(ALL_CXXFLAGS) -c $(FSW)/c++/fen_monitor.cpp -o $@
+
+.PHONY: all clean
 clean:
 	rm -f $(OBJECTS) $(SHLIB)
diff --git a/src/Makevars.ucrt b/src/Makevars.ucrt
deleted file mode 100644
index 8ab10a1..0000000
--- a/src/Makevars.ucrt
+++ /dev/null
@@ -1,17 +0,0 @@
-PKG_CFLAGS = -I../w-install/include $(C_VISIBILITY)
-PKG_LIBS = ../w-install/lib/libfswatch.a -pthread
-
-SOURCES = init.c watcher.c
-OBJECTS = $(SOURCES:.c=.o)
-
-.PHONY: all cleaup clean
-
-all: cleanup
-
-cleanup: $(SHLIB)
-	@rm -rf ../w-install
-
-$(SHLIB): $(OBJECTS)
-
-clean:
-	rm -f $(OBJECTS) $(SHLIB)
diff --git a/src/Makevars.ucrt.in b/src/Makevars.ucrt.in
new file mode 100644
index 0000000..ae844ee
--- /dev/null
+++ b/src/Makevars.ucrt.in
@@ -0,0 +1,63 @@
+# Generated by tools/update_libfswatch.sh -- do not edit by hand.
+# Template: configure.ucrt fills in the C++ standard line to produce
+# src/Makevars.ucrt.
+#
+# Rtools42/43/44 (gcc 10/12/13). Identical to Makevars.win except that
+# std::filesystem is folded into libstdc++, so -lstdc++fs is not needed, and the
+# CXX_STD request is emitted only on R < 4.3 (R >= 4.3 defaults to C++17;
+# specifying it then trips a CRAN "please drop specification" NOTE).
+PKG_CPPFLAGS = -Ifswatch/libfswatch/src
+PKG_CFLAGS = $(C_VISIBILITY)
+PKG_CXXFLAGS = $(CXX_VISIBILITY)
+PKG_LIBS = -pthread
+
+@cxx_std@
+
+P_OBJECTS = init.o watcher.o
+FSW = fswatch/libfswatch/src/libfswatch
+FSW_OBJECTS = $(FSW)/c/cevent.o $(FSW)/c/libfswatch.o $(FSW)/c/libfswatch_log.o $(FSW)/c++/event.o $(FSW)/c++/filter.o $(FSW)/c++/libfswatch_exception.o $(FSW)/c++/monitor.o $(FSW)/c++/monitor_factory.o $(FSW)/c++/path_utils.o $(FSW)/c++/poll_monitor.o $(FSW)/c++/string/string_utils.o $(FSW)/c++/windows_monitor.o $(FSW)/c++/windows/win_directory_change_event.o $(FSW)/c++/windows/win_error_message.o $(FSW)/c++/windows/win_handle.o $(FSW)/c++/windows/win_paths.o $(FSW)/c++/windows/win_strings.o
+
+OBJECTS = $(P_OBJECTS) $(FSW_OBJECTS)
+
+all: $(SHLIB)
+
+$(SHLIB): $(OBJECTS)
+
+$(FSW)/c/cevent.o: $(FSW)/c/cevent.cpp
+	$(CXX) $(ALL_CPPFLAGS) $(ALL_CXXFLAGS) -c $(FSW)/c/cevent.cpp -o $@
+$(FSW)/c/libfswatch.o: $(FSW)/c/libfswatch.cpp
+	$(CXX) $(ALL_CPPFLAGS) $(ALL_CXXFLAGS) -c $(FSW)/c/libfswatch.cpp -o $@
+$(FSW)/c/libfswatch_log.o: $(FSW)/c/libfswatch_log.cpp
+	$(CXX) $(ALL_CPPFLAGS) $(ALL_CXXFLAGS) -c $(FSW)/c/libfswatch_log.cpp -o $@
+$(FSW)/c++/event.o: $(FSW)/c++/event.cpp
+	$(CXX) $(ALL_CPPFLAGS) $(ALL_CXXFLAGS) -c $(FSW)/c++/event.cpp -o $@
+$(FSW)/c++/filter.o: $(FSW)/c++/filter.cpp
+	$(CXX) $(ALL_CPPFLAGS) $(ALL_CXXFLAGS) -c $(FSW)/c++/filter.cpp -o $@
+$(FSW)/c++/libfswatch_exception.o: $(FSW)/c++/libfswatch_exception.cpp
+	$(CXX) $(ALL_CPPFLAGS) $(ALL_CXXFLAGS) -c $(FSW)/c++/libfswatch_exception.cpp -o $@
+$(FSW)/c++/monitor.o: $(FSW)/c++/monitor.cpp
+	$(CXX) $(ALL_CPPFLAGS) $(ALL_CXXFLAGS) -c $(FSW)/c++/monitor.cpp -o $@
+$(FSW)/c++/monitor_factory.o: $(FSW)/c++/monitor_factory.cpp
+	$(CXX) $(ALL_CPPFLAGS) $(ALL_CXXFLAGS) -c $(FSW)/c++/monitor_factory.cpp -o $@
+$(FSW)/c++/path_utils.o: $(FSW)/c++/path_utils.cpp
+	$(CXX) $(ALL_CPPFLAGS) $(ALL_CXXFLAGS) -c $(FSW)/c++/path_utils.cpp -o $@
+$(FSW)/c++/poll_monitor.o: $(FSW)/c++/poll_monitor.cpp
+	$(CXX) $(ALL_CPPFLAGS) $(ALL_CXXFLAGS) -c $(FSW)/c++/poll_monitor.cpp -o $@
+$(FSW)/c++/string/string_utils.o: $(FSW)/c++/string/string_utils.cpp
+	$(CXX) $(ALL_CPPFLAGS) $(ALL_CXXFLAGS) -c $(FSW)/c++/string/string_utils.cpp -o $@
+$(FSW)/c++/windows_monitor.o: $(FSW)/c++/windows_monitor.cpp
+	$(CXX) $(ALL_CPPFLAGS) $(ALL_CXXFLAGS) -c $(FSW)/c++/windows_monitor.cpp -o $@
+$(FSW)/c++/windows/win_directory_change_event.o: $(FSW)/c++/windows/win_directory_change_event.cpp
+	$(CXX) $(ALL_CPPFLAGS) $(ALL_CXXFLAGS) -c $(FSW)/c++/windows/win_directory_change_event.cpp -o $@
+$(FSW)/c++/windows/win_error_message.o: $(FSW)/c++/windows/win_error_message.cpp
+	$(CXX) $(ALL_CPPFLAGS) $(ALL_CXXFLAGS) -c $(FSW)/c++/windows/win_error_message.cpp -o $@
+$(FSW)/c++/windows/win_handle.o: $(FSW)/c++/windows/win_handle.cpp
+	$(CXX) $(ALL_CPPFLAGS) $(ALL_CXXFLAGS) -c $(FSW)/c++/windows/win_handle.cpp -o $@
+$(FSW)/c++/windows/win_paths.o: $(FSW)/c++/windows/win_paths.cpp
+	$(CXX) $(ALL_CPPFLAGS) $(ALL_CXXFLAGS) -c $(FSW)/c++/windows/win_paths.cpp -o $@
+$(FSW)/c++/windows/win_strings.o: $(FSW)/c++/windows/win_strings.cpp
+	$(CXX) $(ALL_CPPFLAGS) $(ALL_CXXFLAGS) -c $(FSW)/c++/windows/win_strings.cpp -o $@
+
+.PHONY: all clean
+clean:
+	rm -f $(OBJECTS) $(SHLIB)
diff --git a/src/Makevars.win b/src/Makevars.win
index b1dd878..8dea2d0 100644
--- a/src/Makevars.win
+++ b/src/Makevars.win
@@ -1,17 +1,65 @@
-PKG_CFLAGS = -I../w-install${R_ARCH}/include $(C_VISIBILITY)
-PKG_LIBS = ../w-install${R_ARCH}/lib/libfswatch.a -pthread -lstdc++fs
+# Generated by tools/update_libfswatch.sh -- do not edit by hand.
+#
+# Rtools40 (gcc 8.3), dual i386 + x64. Always compiles the bundled libfswatch
+# (no system-library path on Windows). std::filesystem is used in the common
+# core, so -lstdc++fs is required on gcc 8.x/9.x.
+#
+# CXX_STD stays static here: Rtools40 only ever serves R <= 4.1 (< 4.3), whose
+# default is below C++17, so requesting it is always needed and never trips the
+# CRAN "please drop specification" NOTE. (UCRT is conditional -- see
+# Makevars.ucrt.in / configure.ucrt.)
+PKG_CPPFLAGS = -Ifswatch/libfswatch/src
+PKG_CFLAGS = $(C_VISIBILITY)
+PKG_CXXFLAGS = $(CXX_VISIBILITY)
+PKG_LIBS = -pthread -lstdc++fs
 
-SOURCES = init.c watcher.c
-OBJECTS = $(SOURCES:.c=.o)
+CXX_STD = CXX17
 
-.PHONY: all cleanup clean
+P_OBJECTS = init.o watcher.o
+FSW = fswatch/libfswatch/src/libfswatch
+FSW_OBJECTS = $(FSW)/c/cevent.o $(FSW)/c/libfswatch.o $(FSW)/c/libfswatch_log.o $(FSW)/c++/event.o $(FSW)/c++/filter.o $(FSW)/c++/libfswatch_exception.o $(FSW)/c++/monitor.o $(FSW)/c++/monitor_factory.o $(FSW)/c++/path_utils.o $(FSW)/c++/poll_monitor.o $(FSW)/c++/string/string_utils.o $(FSW)/c++/windows_monitor.o $(FSW)/c++/windows/win_directory_change_event.o $(FSW)/c++/windows/win_error_message.o $(FSW)/c++/windows/win_handle.o $(FSW)/c++/windows/win_paths.o $(FSW)/c++/windows/win_strings.o
 
-all: cleanup
+OBJECTS = $(P_OBJECTS) $(FSW_OBJECTS)
 
-cleanup: $(SHLIB)
-	@rm -rf ../w-install${R_ARCH}
+all: $(SHLIB)
 
 $(SHLIB): $(OBJECTS)
 
+$(FSW)/c/cevent.o: $(FSW)/c/cevent.cpp
+	$(CXX) $(ALL_CPPFLAGS) $(ALL_CXXFLAGS) -c $(FSW)/c/cevent.cpp -o $@
+$(FSW)/c/libfswatch.o: $(FSW)/c/libfswatch.cpp
+	$(CXX) $(ALL_CPPFLAGS) $(ALL_CXXFLAGS) -c $(FSW)/c/libfswatch.cpp -o $@
+$(FSW)/c/libfswatch_log.o: $(FSW)/c/libfswatch_log.cpp
+	$(CXX) $(ALL_CPPFLAGS) $(ALL_CXXFLAGS) -c $(FSW)/c/libfswatch_log.cpp -o $@
+$(FSW)/c++/event.o: $(FSW)/c++/event.cpp
+	$(CXX) $(ALL_CPPFLAGS) $(ALL_CXXFLAGS) -c $(FSW)/c++/event.cpp -o $@
+$(FSW)/c++/filter.o: $(FSW)/c++/filter.cpp
+	$(CXX) $(ALL_CPPFLAGS) $(ALL_CXXFLAGS) -c $(FSW)/c++/filter.cpp -o $@
+$(FSW)/c++/libfswatch_exception.o: $(FSW)/c++/libfswatch_exception.cpp
+	$(CXX) $(ALL_CPPFLAGS) $(ALL_CXXFLAGS) -c $(FSW)/c++/libfswatch_exception.cpp -o $@
+$(FSW)/c++/monitor.o: $(FSW)/c++/monitor.cpp
+	$(CXX) $(ALL_CPPFLAGS) $(ALL_CXXFLAGS) -c $(FSW)/c++/monitor.cpp -o $@
+$(FSW)/c++/monitor_factory.o: $(FSW)/c++/monitor_factory.cpp
+	$(CXX) $(ALL_CPPFLAGS) $(ALL_CXXFLAGS) -c $(FSW)/c++/monitor_factory.cpp -o $@
+$(FSW)/c++/path_utils.o: $(FSW)/c++/path_utils.cpp
+	$(CXX) $(ALL_CPPFLAGS) $(ALL_CXXFLAGS) -c $(FSW)/c++/path_utils.cpp -o $@
+$(FSW)/c++/poll_monitor.o: $(FSW)/c++/poll_monitor.cpp
+	$(CXX) $(ALL_CPPFLAGS) $(ALL_CXXFLAGS) -c $(FSW)/c++/poll_monitor.cpp -o $@
+$(FSW)/c++/string/string_utils.o: $(FSW)/c++/string/string_utils.cpp
+	$(CXX) $(ALL_CPPFLAGS) $(ALL_CXXFLAGS) -c $(FSW)/c++/string/string_utils.cpp -o $@
+$(FSW)/c++/windows_monitor.o: $(FSW)/c++/windows_monitor.cpp
+	$(CXX) $(ALL_CPPFLAGS) $(ALL_CXXFLAGS) -c $(FSW)/c++/windows_monitor.cpp -o $@
+$(FSW)/c++/windows/win_directory_change_event.o: $(FSW)/c++/windows/win_directory_change_event.cpp
+	$(CXX) $(ALL_CPPFLAGS) $(ALL_CXXFLAGS) -c $(FSW)/c++/windows/win_directory_change_event.cpp -o $@
+$(FSW)/c++/windows/win_error_message.o: $(FSW)/c++/windows/win_error_message.cpp
+	$(CXX) $(ALL_CPPFLAGS) $(ALL_CXXFLAGS) -c $(FSW)/c++/windows/win_error_message.cpp -o $@
+$(FSW)/c++/windows/win_handle.o: $(FSW)/c++/windows/win_handle.cpp
+	$(CXX) $(ALL_CPPFLAGS) $(ALL_CXXFLAGS) -c $(FSW)/c++/windows/win_handle.cpp -o $@
+$(FSW)/c++/windows/win_paths.o: $(FSW)/c++/windows/win_paths.cpp
+	$(CXX) $(ALL_CPPFLAGS) $(ALL_CXXFLAGS) -c $(FSW)/c++/windows/win_paths.cpp -o $@
+$(FSW)/c++/windows/win_strings.o: $(FSW)/c++/windows/win_strings.cpp
+	$(CXX) $(ALL_CPPFLAGS) $(ALL_CXXFLAGS) -c $(FSW)/c++/windows/win_strings.cpp -o $@
+
+.PHONY: all clean
 clean:
 	rm -f $(OBJECTS) $(SHLIB)
diff --git a/src/fswatch/CMakeLists.txt b/src/fswatch/CMakeLists.txt
deleted file mode 100644
index 6fff8ec..0000000
--- a/src/fswatch/CMakeLists.txt
+++ /dev/null
@@ -1,83 +0,0 @@
-#
-# Copyright (c) 2014-2026 Enrico M. Crisostomo
-#
-# This program is free software; you can redistribute it and/or modify it under
-# the terms of the GNU General Public License as published by the Free Software
-# Foundation; either version 3, or (at your option) any later version.
-#
-# This program is distributed in the hope that it will be useful, but WITHOUT
-# ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
-# FOR A PARTICULAR PURPOSE.  See the GNU General Public License for more
-# details.
-#
-# You should have received a copy of the GNU General Public License along with
-# this program.  If not, see <http://www.gnu.org/licenses/>.
-#
-cmake_minimum_required(VERSION 3.14)
-project(fswatch VERSION 1.20.1 LANGUAGES C CXX)
-
-set(VERSION_MODIFIER "")
-set(FULL_VERSION "${PROJECT_VERSION}${VERSION_MODIFIER}")
-
-#@formatter:off
-set(PACKAGE           "${PROJECT_NAME}")
-set(PACKAGE_NAME      "${PACKAGE}")
-set(PACKAGE_VERSION   "${FULL_VERSION}")
-set(PACKAGE_STRING    "${PACKAGE_NAME} ${PACKAGE_VERSION}")
-set(PACKAGE_AUTHOR    "enrico.m.crisostomo@gmail.com")
-set(PACKAGE_BUGREPORT "${PACKAGE_AUTHOR}")
-set(PACKAGE_TARNAME   "${PACKAGE}")
-set(PACKAGE_URL       "https://github.com/emcrisostomo/${PACKAGE}")
-set(LOCALEDIR         "${CMAKE_INSTALL_PREFIX}/share/locale" CACHE FILEPATH "locale dir")
-#@formatter:on
-
-if (NOT CMAKE_CXX_STANDARD)
-    set(CMAKE_CXX_STANDARD 17)
-endif ()
-set(CMAKE_CXX_STANDARD_REQUIRED ON)
-set(CMAKE_CXX_EXTENSIONS OFF)
-
-# Add option to choose between shared and static libraries
-option(BUILD_SHARED_LIBS "Build shared libraries" OFF)
-# Add option to build libfswatch only (without fswatch or tests)
-option(BUILD_LIBS_ONLY "Build libfswatch only" OFF)
-
-# include modules
-include(FindGettext)
-include(FindIntl)
-include(CheckIncludeFileCXX)
-include(CheckStructHasMember)
-include(CheckCXXSymbolExists)
-include(CTest)
-
-# check for gettext and libintl
-check_include_file_cxx(getopt.h HAVE_GETOPT_H)
-
-if (HAVE_GETOPT_H)
-    check_cxx_symbol_exists(getopt_long getopt.h HAVE_GETOPT_LONG)
-endif (HAVE_GETOPT_H)
-
-# If both gettext and libintl are found, define the USE_NLS variable to
-# optionally disable them
-if (Intl_FOUND AND GETTEXT_FOUND)
-    option(USE_NLS "Use NLS" ON)
-endif ()
-
-if (USE_NLS)
-    set(ENABLE_NLS 1)
-
-    # gettext configuration
-    set(LINGUAS en en@quot en@boldquot it es)
-
-    foreach (language ${LINGUAS})
-        configure_file(${PROJECT_SOURCE_DIR}/po/${language}.po ${PROJECT_BINARY_DIR}/${language}.po COPYONLY)
-    endforeach ()
-
-    gettext_process_pot_file(po/${PACKAGE}.pot ALL INSTALL_DESTINATION share/locale LANGUAGES ${LINGUAS})
-endif ()
-
-add_subdirectory(libfswatch)
-if (NOT BUILD_LIBS_ONLY)
-add_subdirectory(fswatch/src)
-add_subdirectory(test/src)
-endif ()
diff --git a/src/fswatch/libfswatch/CMakeLists.txt b/src/fswatch/libfswatch/CMakeLists.txt
deleted file mode 100644
index c401d1d..0000000
--- a/src/fswatch/libfswatch/CMakeLists.txt
+++ /dev/null
@@ -1,236 +0,0 @@
-#
-# Copyright (c) 2014-2026 Enrico M. Crisostomo
-#
-# This program is free software; you can redistribute it and/or modify it under
-# the terms of the GNU General Public License as published by the Free Software
-# Foundation; either version 3, or (at your option) any later version.
-#
-# This program is distributed in the hope that it will be useful, but WITHOUT
-# ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
-# FOR A PARTICULAR PURPOSE.  See the GNU General Public License for more
-# details.
-#
-# You should have received a copy of the GNU General Public License along with
-# this program.  If not, see <http://www.gnu.org/licenses/>.
-#
-
-# Define symbols to conditionally define FSEvents flags
-if(APPLE)
-    if (${CMAKE_SYSTEM_VERSION} VERSION_GREATER_EQUAL "9.0")
-        set(HAVE_MACOS_GE_10_5 1)
-    endif()
-
-    if (${CMAKE_SYSTEM_VERSION} VERSION_GREATER_EQUAL "10.0")
-        set(HAVE_MACOS_GE_10_6 1)
-    endif()
-
-    if (${CMAKE_SYSTEM_VERSION} VERSION_GREATER_EQUAL "11.0")
-        set(HAVE_MACOS_GE_10_7 1)
-    endif()
-
-    if (${CMAKE_SYSTEM_VERSION} VERSION_GREATER_EQUAL "13.0")
-        set(HAVE_MACOS_GE_10_9 1)
-    endif()
-
-    if (${CMAKE_SYSTEM_VERSION} VERSION_GREATER_EQUAL "14.0")
-        set(HAVE_MACOS_GE_10_10 1)
-    endif()
-
-    if (${CMAKE_SYSTEM_VERSION} VERSION_GREATER_EQUAL "17.0")
-        set(HAVE_MACOS_GE_10_13 1)
-    endif()
-endif()
-
-set(LIBFSWATCH_HEADER_FILES
-        src/libfswatch/c/cevent.h
-        src/libfswatch/c/cfilter.h
-        src/libfswatch/c/cmonitor.h
-        src/libfswatch/c/error.h
-        src/libfswatch/c/libfswatch.h
-        src/libfswatch/c/libfswatch_log.h
-        src/libfswatch/c/libfswatch_types.h
-        src/libfswatch/c++/event.hpp
-        src/libfswatch/c++/filter.hpp
-        src/libfswatch/c++/libfswatch_exception.hpp
-        src/libfswatch/c++/monitor.hpp
-        src/libfswatch/c++/monitor_factory.hpp
-        src/libfswatch/c++/path_utils.hpp
-        src/libfswatch/c++/poll_monitor.hpp
-        src/libfswatch/c++/string/string_utils.hpp
-        src/libfswatch/gettext.h
-        src/libfswatch/gettext_defs.h
-        ${CMAKE_CURRENT_BINARY_DIR}/libfswatch_config.h)
-
-set(LIB_SOURCE_FILES
-        src/libfswatch/c/cevent.cpp
-        src/libfswatch/c/libfswatch.cpp
-        src/libfswatch/c/libfswatch_log.cpp
-        src/libfswatch/c++/event.cpp
-        src/libfswatch/c++/filter.cpp
-        src/libfswatch/c++/libfswatch_exception.cpp
-        src/libfswatch/c++/monitor.cpp
-        src/libfswatch/c++/monitor_factory.cpp
-        src/libfswatch/c++/path_utils.cpp
-        src/libfswatch/c++/poll_monitor.cpp
-        src/libfswatch/c++/string/string_utils.cpp)
-
-check_struct_has_member("struct stat" st_mtime sys/stat.h HAVE_STRUCT_STAT_ST_MTIME)
-check_struct_has_member("struct stat" st_mtimespec sys/stat.h HAVE_STRUCT_STAT_ST_MTIMESPEC)
-
-check_include_file_cxx(sys/inotify.h HAVE_SYS_INOTIFY_H)
-check_include_file_cxx(sys/epoll.h HAVE_SYS_EPOLL_H)
-check_include_file_cxx(sys/eventfd.h HAVE_SYS_EVENTFD_H)
-
-if (HAVE_SYS_INOTIFY_H AND HAVE_SYS_EPOLL_H AND HAVE_SYS_EVENTFD_H)
-    set(CMAKE_REQUIRED_DEFINITIONS_SAVED ${CMAKE_REQUIRED_DEFINITIONS})
-    list(APPEND CMAKE_REQUIRED_DEFINITIONS -D_GNU_SOURCE)
-    check_cxx_symbol_exists(inotify_init1 sys/inotify.h HAVE_INOTIFY_INIT1)
-    check_cxx_symbol_exists(epoll_create1 sys/epoll.h HAVE_EPOLL_CREATE1)
-    check_cxx_symbol_exists(eventfd sys/eventfd.h HAVE_EVENTFD)
-    set(CMAKE_REQUIRED_DEFINITIONS ${CMAKE_REQUIRED_DEFINITIONS_SAVED})
-endif ()
-
-if (HAVE_SYS_INOTIFY_H AND HAVE_SYS_EPOLL_H AND HAVE_SYS_EVENTFD_H AND
-        HAVE_INOTIFY_INIT1 AND HAVE_EPOLL_CREATE1 AND HAVE_EVENTFD)
-    set(HAVE_INOTIFY_MONITOR 1 CACHE INTERNAL "Linux inotify monitor is available")
-    set(LIBFSWATCH_HEADER_FILES
-            ${LIBFSWATCH_HEADER_FILES}
-            src/libfswatch/c++/inotify_monitor.hpp)
-    set(LIB_SOURCE_FILES
-            ${LIB_SOURCE_FILES}
-            src/libfswatch/c++/inotify_monitor.cpp)
-endif ()
-
-check_include_file_cxx(sys/fanotify.h HAVE_SYS_FANOTIFY_H)
-check_include_file_cxx(sys/epoll.h HAVE_SYS_EPOLL_H)
-check_include_file_cxx(sys/eventfd.h HAVE_SYS_EVENTFD_H)
-
-if (HAVE_SYS_FANOTIFY_H AND HAVE_SYS_EPOLL_H AND HAVE_SYS_EVENTFD_H)
-    check_cxx_symbol_exists(fanotify_init sys/fanotify.h HAVE_FANOTIFY_INIT)
-    check_cxx_symbol_exists(fanotify_mark sys/fanotify.h HAVE_FANOTIFY_MARK)
-    check_cxx_symbol_exists(epoll_create1 sys/epoll.h HAVE_EPOLL_CREATE1)
-    check_cxx_symbol_exists(epoll_ctl sys/epoll.h HAVE_EPOLL_CTL)
-    check_cxx_symbol_exists(epoll_wait sys/epoll.h HAVE_EPOLL_WAIT)
-    check_cxx_symbol_exists(eventfd sys/eventfd.h HAVE_EVENTFD)
-    check_cxx_symbol_exists(FAN_REPORT_DFID_NAME sys/fanotify.h HAVE_FAN_REPORT_DFID_NAME)
-    check_cxx_symbol_exists(FAN_CREATE sys/fanotify.h HAVE_FAN_CREATE)
-    check_cxx_symbol_exists(FAN_DELETE sys/fanotify.h HAVE_FAN_DELETE)
-    check_cxx_symbol_exists(FAN_MOVED_FROM sys/fanotify.h HAVE_FAN_MOVED_FROM)
-    check_cxx_symbol_exists(FAN_MOVED_TO sys/fanotify.h HAVE_FAN_MOVED_TO)
-    check_cxx_symbol_exists(FAN_EVENT_ON_CHILD sys/fanotify.h HAVE_FAN_EVENT_ON_CHILD)
-    check_cxx_symbol_exists(FAN_Q_OVERFLOW sys/fanotify.h HAVE_FAN_Q_OVERFLOW)
-
-    if (HAVE_FANOTIFY_INIT AND HAVE_FANOTIFY_MARK AND
-        HAVE_EPOLL_CREATE1 AND HAVE_EPOLL_CTL AND HAVE_EPOLL_WAIT AND HAVE_EVENTFD AND
-        HAVE_FAN_REPORT_DFID_NAME AND HAVE_FAN_CREATE AND HAVE_FAN_DELETE AND
-        HAVE_FAN_MOVED_FROM AND HAVE_FAN_MOVED_TO AND
-        HAVE_FAN_EVENT_ON_CHILD AND HAVE_FAN_Q_OVERFLOW)
-        set(HAVE_FANOTIFY ON CACHE BOOL "Enable fanotify support")
-        set(LIBFSWATCH_HEADER_FILES
-                ${LIBFSWATCH_HEADER_FILES}
-                src/libfswatch/c++/fanotify_monitor.hpp)
-        set(LIB_SOURCE_FILES
-                ${LIB_SOURCE_FILES}
-                src/libfswatch/c++/fanotify_monitor.cpp)
-    endif ()
-endif ()
-
-check_include_file_cxx(sys/event.h HAVE_SYS_EVENT_H)
-
-if (HAVE_SYS_EVENT_H)
-    set(LIBFSWATCH_HEADER_FILES
-            ${LIBFSWATCH_HEADER_FILES}
-            src/libfswatch/c++/kqueue_monitor.hpp)
-    set(LIB_SOURCE_FILES
-            ${LIB_SOURCE_FILES}
-            src/libfswatch/c++/kqueue_monitor.cpp)
-endif (HAVE_SYS_EVENT_H)
-
-check_include_file_cxx(port.h HAVE_PORT_H)
-
-if (HAVE_PORT_H)
-    set(LIBFSWATCH_HEADER_FILES
-            ${LIBFSWATCH_HEADER_FILES}
-            src/libfswatch/c++/fen_monitor.hpp)
-    set(LIB_SOURCE_FILES
-            ${LIB_SOURCE_FILES}
-            src/libfswatch/c++/fen_monitor.cpp)
-endif (HAVE_PORT_H)
-
-check_cxx_symbol_exists(FindFirstChangeNotification windows.h HAVE_WINDOWS_HEADER)
-
-if (HAVE_WINDOWS_HEADER)
-
-    set(LIBFSWATCH_HEADER_FILES
-            ${LIBFSWATCH_HEADER_FILES}
-            src/libfswatch/c++/windows/win_directory_change_event.hpp
-            src/libfswatch/c++/windows/win_error_message.hpp
-            src/libfswatch/c++/windows/win_handle.hpp
-            src/libfswatch/c++/windows/win_paths.hpp
-            src/libfswatch/c++/windows/win_strings.hpp
-            src/libfswatch/c++/windows_monitor.hpp)
-
-    set(LIB_SOURCE_FILES
-            ${LIB_SOURCE_FILES}
-            src/libfswatch/c++/windows/win_directory_change_event.cpp
-            src/libfswatch/c++/windows/win_error_message.cpp
-            src/libfswatch/c++/windows/win_handle.cpp
-            src/libfswatch/c++/windows/win_paths.cpp
-            src/libfswatch/c++/windows/win_strings.cpp
-            src/libfswatch/c++/windows_monitor.cpp)
-    set(HAVE_WINDOWS ON CACHE BOOL "Enable Windows support")
-
-endif (HAVE_WINDOWS_HEADER)
-
-if (APPLE)
-    check_include_file_cxx(CoreServices/CoreServices.h HAVE_FSEVENTS_FILE_EVENTS)
-
-    if (HAVE_FSEVENTS_FILE_EVENTS)
-        find_library(CORESERVICES_LIBRARY CoreServices)
-
-        if (CORESERVICES_LIBRARY)
-            set(CMAKE_REQUIRED_LIBRARIES ${CORESERVICES_LIBRARY})
-            check_symbol_exists(FSEventStreamSetDispatchQueue "CoreServices/CoreServices.h" HAVE_FSEVENTS_FSEVENTSTREAMSETDISPATCHQUEUE)
-
-            if (HAVE_FSEVENTS_FSEVENTSTREAMSETDISPATCHQUEUE)
-                set(EXTRA_LIBS ${EXTRA_LIBS} ${CORESERVICES_LIBRARY})
-                set(LIBFSWATCH_HEADER_FILES
-                    ${LIBFSWATCH_HEADER_FILES}
-                    src/libfswatch/c++/fsevents_monitor.hpp)
-                set(LIB_SOURCE_FILES
-                    ${LIB_SOURCE_FILES}
-                    src/libfswatch/c++/fsevents_monitor.cpp)
-            endif (HAVE_FSEVENTS_FSEVENTSTREAMSETDISPATCHQUEUE)
-        endif ()
-    endif (HAVE_FSEVENTS_FILE_EVENTS)
-endif (APPLE)
-
-# Add a configuration file processed by cmake
-configure_file(libfswatch_config.in libfswatch_config.h)
-# TODO: consider removing it
-add_definitions(-DHAVE_LIBFSWATCH_CONFIG_H)
-
-add_library(libfswatch ${LIB_SOURCE_FILES} ${LIBFSWATCH_HEADER_FILES})
-set_target_properties(libfswatch PROPERTIES PREFIX "")
-
-# check for gettext and libintl
-if (USE_NLS)
-    if (Intl_LIBRARIES)
-        target_link_libraries(libfswatch PRIVATE ${Intl_LIBRARIES})
-    endif ()
-endif ()
-
-target_include_directories(libfswatch PUBLIC src/libfswatch)
-target_include_directories(libfswatch PUBLIC src)
-target_include_directories(libfswatch PUBLIC ${Intl_INCLUDE_DIRS})
-target_include_directories(libfswatch PRIVATE ${PROJECT_BINARY_DIR})
-target_include_directories(libfswatch PRIVATE ${CMAKE_CURRENT_BINARY_DIR})
-target_link_libraries(libfswatch PRIVATE ${EXTRA_LIBS})
-
-install(TARGETS libfswatch LIBRARY DESTINATION lib)
-# TODO: should migrate to target_source(file_set) to install headers
-install(DIRECTORY src/libfswatch
-    DESTINATION include
-    FILES_MATCHING
-    PATTERN "*.hpp"
-    PATTERN "*.h")
diff --git a/src/fswatch/libfswatch/libfswatch_config.in b/src/fswatch/libfswatch/libfswatch_config.in
deleted file mode 100644
index 330feba..0000000
--- a/src/fswatch/libfswatch/libfswatch_config.in
+++ /dev/null
@@ -1,46 +0,0 @@
-/*
- * Copyright (c) 2026 Enrico M. Crisostomo
- *
- * This program is free software; you can redistribute it and/or modify it under
- * the terms of the GNU General Public License as published by the Free Software
- * Foundation; either version 3, or (at your option) any later version.
- *
- * This program is distributed in the hope that it will be useful, but WITHOUT
- * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
- * FOR A PARTICULAR PURPOSE.  See the GNU General Public License for more
- * details.
- *
- * You should have received a copy of the GNU General Public License along with
- * this program.  If not, see <http://www.gnu.org/licenses/>.
- */
-
-#cmakedefine ENABLE_NLS        @ENABLE_NLS@
-#cmakedefine LOCALEDIR         "@LOCALEDIR@"
-#cmakedefine PACKAGE           "@PACKAGE@"
-#cmakedefine PACKAGE_NAME      "@PACKAGE_NAME@"
-#cmakedefine PACKAGE_VERSION   "@PACKAGE_VERSION@"
-#cmakedefine PACKAGE_STRING    "@PACKAGE_STRING@"
-#cmakedefine PACKAGE_BUGREPORT "@PACKAGE_BUGREPORT@"
-#cmakedefine PACKAGE_TARNAME   "@PACKAGE_TARNAME@"
-#cmakedefine PACKAGE_URL       "@PACKAGE_URL@"
-#cmakedefine HAVE_GETOPT_LONG
-
-#cmakedefine HAVE_FSEVENTS_FSEVENTSTREAMSETDISPATCHQUEUE
-#cmakedefine HAVE_FANOTIFY
-#cmakedefine HAVE_PORT_H
-#cmakedefine HAVE_STRUCT_STAT_ST_MTIME
-#cmakedefine HAVE_STRUCT_STAT_ST_MTIMESPEC
-#cmakedefine HAVE_INOTIFY_MONITOR
-#cmakedefine HAVE_SYS_EPOLL_H
-#cmakedefine HAVE_SYS_EVENTFD_H
-#cmakedefine HAVE_SYS_EVENT_H
-#cmakedefine HAVE_SYS_FANOTIFY_H
-#cmakedefine HAVE_SYS_INOTIFY_H
-#cmakedefine HAVE_WINDOWS
-
-#cmakedefine HAVE_MACOS_GE_10_5
-#cmakedefine HAVE_MACOS_GE_10_6
-#cmakedefine HAVE_MACOS_GE_10_7
-#cmakedefine HAVE_MACOS_GE_10_9
-#cmakedefine HAVE_MACOS_GE_10_10
-#cmakedefine HAVE_MACOS_GE_10_13
diff --git a/src/fswatch/libfswatch/src/libfswatch.pc.in b/src/fswatch/libfswatch/src/libfswatch.pc.in
deleted file mode 100644
index 34196ce..0000000
--- a/src/fswatch/libfswatch/src/libfswatch.pc.in
+++ /dev/null
@@ -1,12 +0,0 @@
-prefix=@prefix@
-exec_prefix=@exec_prefix@
-libdir=@libdir@
-includedir=@includedir@
-
-Name: libfswatch
-Description: libfswatch
-URL: https://github.com/emcrisostomo/fswatch/tree/master/libfswatch
-Version: @VERSION@
-Requires:
-Libs: -L${libdir} -lfswatch
-Cflags: -I${includedir}
diff --git a/src/fswatch/libfswatch/src/libfswatch/c++/fanotify_monitor.cpp b/src/fswatch/libfswatch/src/libfswatch/c++/fanotify_monitor.cpp
index fa69760..75e2ff9 100644
--- a/src/fswatch/libfswatch/src/libfswatch/c++/fanotify_monitor.cpp
+++ b/src/fswatch/libfswatch/src/libfswatch/c++/fanotify_monitor.cpp
@@ -20,6 +20,8 @@
 
 #include <libfswatch/libfswatch_config.h>
 
+#ifdef HAVE_FANOTIFY
+
 #include "fanotify_monitor.hpp"
 #include "libfswatch/gettext_defs.h"
 #include "libfswatch_exception.hpp"
@@ -734,3 +736,5 @@ namespace fsw
     }
   }
 }
+
+#endif  /* WATCHER guard HAVE_FANOTIFY */
diff --git a/src/fswatch/libfswatch/src/libfswatch/c++/fsevents_monitor.cpp b/src/fswatch/libfswatch/src/libfswatch/c++/fsevents_monitor.cpp
index f3862c4..112b093 100644
--- a/src/fswatch/libfswatch/src/libfswatch/c++/fsevents_monitor.cpp
+++ b/src/fswatch/libfswatch/src/libfswatch/c++/fsevents_monitor.cpp
@@ -14,6 +14,8 @@
  * this program.  If not, see <http://www.gnu.org/licenses/>.
  */
 #include <libfswatch/libfswatch_config.h>
+
+#ifdef HAVE_FSEVENTS_FSEVENTSTREAMSETDISPATCHQUEUE
 #include <memory>
 #include <unistd.h> // isatty()
 #include <cstdio> // fileno()
@@ -267,7 +269,6 @@ namespace fsw
       std::vector<char> path_buffer(max_path_size);
       if (!CFStringGetCString(path, path_buffer.data(), max_path_size, kCFStringEncodingUTF8))
       {
-          std::cerr << "Warning: Failed to convert CFStringRef to C string." << std::endl;
           continue;
       }
 
@@ -363,3 +364,5 @@ namespace fsw
                                  streamFlags);
   }
 }
+
+#endif  /* WATCHER guard HAVE_FSEVENTS_FSEVENTSTREAMSETDISPATCHQUEUE */
diff --git a/src/fswatch/libfswatch/src/libfswatch/c++/inotify_monitor.cpp b/src/fswatch/libfswatch/src/libfswatch/c++/inotify_monitor.cpp
index a8077d8..7931464 100644
--- a/src/fswatch/libfswatch/src/libfswatch/c++/inotify_monitor.cpp
+++ b/src/fswatch/libfswatch/src/libfswatch/c++/inotify_monitor.cpp
@@ -19,6 +19,8 @@
 
 #include <libfswatch/libfswatch_config.h>
 
+#ifdef HAVE_INOTIFY_MONITOR
+
 #include "libfswatch/gettext_defs.h"
 #include "inotify_monitor.hpp"
 #include <algorithm>
@@ -645,3 +647,5 @@ namespace fsw
     }
   }
 }
+
+#endif  /* WATCHER guard HAVE_INOTIFY_MONITOR */
diff --git a/src/fswatch/libfswatch/src/libfswatch/c++/windows/win_directory_change_event.cpp b/src/fswatch/libfswatch/src/libfswatch/c++/windows/win_directory_change_event.cpp
index a7d3be2..9dd93e5 100644
--- a/src/fswatch/libfswatch/src/libfswatch/c++/windows/win_directory_change_event.cpp
+++ b/src/fswatch/libfswatch/src/libfswatch/c++/windows/win_directory_change_event.cpp
@@ -148,7 +148,6 @@ namespace fsw
       }
       else
       {
-        cerr << _("File name unexpectedly empty.") << endl;
       }
 
       curr_entry = (currEntry->NextEntryOffset == 0) ? nullptr : curr_entry + currEntry->NextEntryOffset;
diff --git a/src/fswatch/libfswatch/src/libfswatch/c++/windows_monitor.cpp b/src/fswatch/libfswatch/src/libfswatch/c++/windows_monitor.cpp
index 12eaae5..e43e44c 100644
--- a/src/fswatch/libfswatch/src/libfswatch/c++/windows_monitor.cpp
+++ b/src/fswatch/libfswatch/src/libfswatch/c++/windows_monitor.cpp
@@ -108,7 +108,6 @@ namespace fsw
 
     if (!win_handle::is_valid(h))
     {
-      fprintf(stderr, _("Invalid handle when opening %s.\n"), win_strings::wstring_to_string(path).c_str());
       return false;
     }
 
diff --git a/src/fswatch/libfswatch/src/libfswatch/c/libfswatch_log.cpp b/src/fswatch/libfswatch/src/libfswatch/c/libfswatch_log.cpp
index bbcf4c0..0ca5126 100644
--- a/src/fswatch/libfswatch/src/libfswatch/c/libfswatch_log.cpp
+++ b/src/fswatch/libfswatch/src/libfswatch/c/libfswatch_log.cpp
@@ -13,61 +13,14 @@
  * You should have received a copy of the GNU General Public License along with
  * this program.  If not, see <http://www.gnu.org/licenses/>.
  */
-#include "libfswatch.h"
+/* watcher: logging neutered. libfswatch's diagnostics must not write to
+ * stdout/stderr from compiled code; watcher never enables verbose logging,
+ * so these are no-ops in normal use. See tools/patch_libfswatch.sh. */
 #include "libfswatch_log.h"
-#include "../c++/string/string_utils.hpp"
-#include <cstdarg>
 
-using namespace std;
-using namespace fsw;
-
-void fsw_log(const char *msg)
-{
-  if (fsw_is_verbose()) printf("%s", msg);
-}
-
-void fsw_flog(FILE *f, const char *msg)
-{
-  if (fsw_is_verbose()) fprintf(f, "%s", msg);
-}
-
-void fsw_logf(const char *format, ...)
-{
-  if (!fsw_is_verbose()) return;
-
-  va_list args;
-  va_start(args, format);
-
-  vfprintf(stdout, format, args);
-
-  va_end(args);
-}
-
-void fsw_flogf(FILE *f, const char *format, ...)
-{
-  if (!fsw_is_verbose()) return;
-
-  va_list args;
-  va_start(args, format);
-
-  vfprintf(f, format, args);
-
-  va_end(args);
-}
-
-void fsw_log_perror(const char *msg)
-{
-  if (fsw_is_verbose()) perror(msg);
-}
-
-void fsw_logf_perror(const char *format, ...)
-{
-  if (!fsw_is_verbose()) return;
-
-  va_list args;
-  va_start(args, format);
-
-  perror(string_utils::vstring_from_format(format, args).c_str());
-
-  va_end(args);
-}
+void fsw_log(const char *) {}
+void fsw_flog(FILE *, const char *) {}
+void fsw_logf(const char *, ...) {}
+void fsw_flogf(FILE *, const char *, ...) {}
+void fsw_log_perror(const char *) {}
+void fsw_logf_perror(const char *, ...) {}
diff --git a/src/fswatch/libfswatch/src/libfswatch/c/libfswatch_log.h b/src/fswatch/libfswatch/src/libfswatch/c/libfswatch_log.h
index f061328..5b070e4 100644
--- a/src/fswatch/libfswatch/src/libfswatch/c/libfswatch_log.h
+++ b/src/fswatch/libfswatch/src/libfswatch/c/libfswatch_log.h
@@ -65,30 +65,30 @@ void fsw_logf_perror(const char * format, ...);
  * @brief Log the specified message to the standard output prepended by the
  * source line number.
  */
-#  define FSW_LOG(msg)           fsw_logf("%s: ", __func__);          fsw_log(msg)
+#  define FSW_LOG(msg) ((void)0)
 
 /**
  * @brief Log the specified message to the standard error prepended by the
  * source line number.
  */
-#  define FSW_ELOG(msg)          fsw_flogf(stderr, "%s: ", __func__); fsw_flog(stderr, msg)
+#  define FSW_ELOG(msg) ((void)0)
 
 /**
  * @brief Log the specified `printf()`-like message to the standard output
  * prepended by the source line number.
  */
-#  define FSW_LOGF(msg, ...)     fsw_logf("%s: ", __func__);          fsw_logf(msg, __VA_ARGS__)
+#  define FSW_LOGF(msg, ...) ((void)0)
 
 /**
  * @brief Log the specified `printf()`-like message to the standard error
  * prepended by the source line number.
  */
-#  define FSW_ELOGF(msg, ...)    fsw_flogf(stderr, "%s: ", __func__); fsw_flogf(stderr, msg, __VA_ARGS__)
+#  define FSW_ELOGF(msg, ...) ((void)0)
 
 /**
  * @brief Log the specified `printf()`-like message to the specified file
  * descriptor prepended by the source line number.
  */
-#  define FSW_FLOGF(f, msg, ...) fsw_flogf(f, "%s: ", __func__);      fsw_flogf(f, msg, __VA_ARGS__)
+#  define FSW_FLOGF(f, msg, ...) ((void)0)
 
 #endif  /* LIBFSW_LOG_H */
diff --git a/src/fswatch/libfswatch/src/libfswatch/libfswatch_config.h b/src/fswatch/libfswatch/src/libfswatch/libfswatch_config.h
new file mode 100644
index 0000000..a163dcb
--- /dev/null
+++ b/src/fswatch/libfswatch/src/libfswatch/libfswatch_config.h
@@ -0,0 +1,65 @@
+/* Hand-maintained replacement for the cmake/autotools-generated config header.
+ * Feature selection is keyed on compiler-predefined platform macros.
+ * Regenerated/owned by the watcher package — not by upstream tooling. */
+#ifndef LIBFSWATCH_CONFIG_H
+#define LIBFSWATCH_CONFIG_H
+
+/* C++17 guarantees these; used by libfswatch_map.hpp / libfswatch_set.hpp */
+#define HAVE_UNORDERED_MAP 1
+#define HAVE_UNORDERED_SET 1
+
+#if defined(__APPLE__)
+/* FSEvents + kqueue. The HAVE_MACOS_GE_* gates are *derived from the deployment
+ * target* (a compile-time "probe" of MAC_OS_X_VERSION_MIN_REQUIRED) rather than
+ * hard-set true: this stays correct for any floor R might use, costs nothing,
+ * and needs no configure machinery. Compare against the named MAC_OS_X_VERSION_*
+ * constants — their numeric encoding changed (1090 vs 101000) at 10.10. */
+#  include <AvailabilityMacros.h>
+#  define HAVE_FSEVENTS_FSEVENTSTREAMSETDISPATCHQUEUE 1
+#  define HAVE_SYS_EVENT_H 1
+#  define HAVE_STRUCT_STAT_ST_MTIMESPEC 1
+#  if MAC_OS_X_VERSION_MIN_REQUIRED >= MAC_OS_X_VERSION_10_5
+#    define HAVE_MACOS_GE_10_5 1
+#  endif
+#  if MAC_OS_X_VERSION_MIN_REQUIRED >= MAC_OS_X_VERSION_10_6
+#    define HAVE_MACOS_GE_10_6 1
+#  endif
+#  if MAC_OS_X_VERSION_MIN_REQUIRED >= MAC_OS_X_VERSION_10_7
+#    define HAVE_MACOS_GE_10_7 1
+#  endif
+#  if MAC_OS_X_VERSION_MIN_REQUIRED >= MAC_OS_X_VERSION_10_9
+#    define HAVE_MACOS_GE_10_9 1
+#  endif
+#  if MAC_OS_X_VERSION_MIN_REQUIRED >= MAC_OS_X_VERSION_10_10
+#    define HAVE_MACOS_GE_10_10 1
+#  endif
+#  if MAC_OS_X_VERSION_MIN_REQUIRED >= MAC_OS_X_VERSION_10_13
+#    define HAVE_MACOS_GE_10_13 1
+#  endif
+
+#elif defined(_WIN32)
+#  define HAVE_WINDOWS 1
+#  define HAVE_STRUCT_STAT_ST_MTIME 1
+
+#elif defined(__linux__)
+#  define HAVE_SYS_INOTIFY_H 1
+#  define HAVE_SYS_EPOLL_H 1
+#  define HAVE_SYS_EVENTFD_H 1
+#  define HAVE_INOTIFY_MONITOR 1
+#  define HAVE_STRUCT_STAT_ST_MTIME 1
+/* fanotify intentionally OFF: requires CAP_SYS_ADMIN/root and a large symbol surface. */
+
+#elif defined(__FreeBSD__) || defined(__OpenBSD__) || defined(__NetBSD__) || defined(__DragonFly__)
+#  define HAVE_SYS_EVENT_H 1
+#  define HAVE_STRUCT_STAT_ST_MTIMESPEC 1
+
+#elif defined(__sun)
+#  define HAVE_PORT_H 1
+#  define HAVE_STRUCT_STAT_ST_MTIME 1
+
+#else
+/* Generic POSIX fallback: stat()-based poll monitor only. */
+#  define HAVE_STRUCT_STAT_ST_MTIME 1
+#endif
+
+#endif /* LIBFSWATCH_CONFIG_H */
diff --git a/tools/fsw_objects_posix.list b/tools/fsw_objects_posix.list
new file mode 100644
index 0000000..c7761d8
--- /dev/null
+++ b/tools/fsw_objects_posix.list
@@ -0,0 +1,16 @@
+$(FSW)/c/cevent.o
+$(FSW)/c/libfswatch.o
+$(FSW)/c/libfswatch_log.o
+$(FSW)/c++/event.o
+$(FSW)/c++/filter.o
+$(FSW)/c++/libfswatch_exception.o
+$(FSW)/c++/monitor.o
+$(FSW)/c++/monitor_factory.o
+$(FSW)/c++/path_utils.o
+$(FSW)/c++/poll_monitor.o
+$(FSW)/c++/string/string_utils.o
+$(FSW)/c++/fsevents_monitor.o
+$(FSW)/c++/kqueue_monitor.o
+$(FSW)/c++/inotify_monitor.o
+$(FSW)/c++/fanotify_monitor.o
+$(FSW)/c++/fen_monitor.o
diff --git a/tools/patch_libfswatch.sh b/tools/patch_libfswatch.sh
new file mode 100755
index 0000000..cfe3f45
--- /dev/null
+++ b/tools/patch_libfswatch.sh
@@ -0,0 +1,140 @@
+#!/bin/bash
+
+# Apply watcher's local patches to the vendored libfswatch sources.
+#
+# Usage: ./tools/patch_libfswatch.sh [LIBFSWATCH_SRC_DIR]
+#
+#   LIBFSWATCH_SRC_DIR defaults to the package's vendored tree
+#   (src/fswatch/libfswatch/src/libfswatch). update_libfswatch.sh passes the
+#   staging tree instead.
+#
+# Every patch is IDEMPOTENT: running this on already-patched sources is a no-op.
+# The patches are:
+#   1. string_utils.cpp  - guard against a null format string (GCC
+#      -Wformat-truncation in stricter CRAN/rhub builds).
+#   2. Monitor self-guards - wrap fsevents/inotify/fanotify monitor bodies in
+#      their platform #ifdef so they compile to empty objects on the wrong OS
+#      (kqueue/fen/windows monitors already self-guard upstream).
+#   3. Logging neutering - libfswatch's diagnostics must not write to
+#      stdout/stderr from compiled code (R CMD check 'compiled code' policy).
+#      watcher never enables libfswatch verbose logging, so this is a no-op in
+#      normal use. Neutering removes the printf/stdout/stderr/cerr symbols that
+#      would otherwise be flagged when libfswatch is compiled into watcher.so.
+
+set -e
+
+GREEN='\033[0;32m'
+YELLOW='\033[1;33m'
+NC='\033[0m'
+
+SCRIPT_DIR=$(cd "$(dirname "$0")" && pwd)
+LIBFSW_SRC="${1:-$SCRIPT_DIR/../src/fswatch/libfswatch/src/libfswatch}"
+
+if [ ! -d "$LIBFSW_SRC" ]; then
+  echo "Error: libfswatch source dir not found: $LIBFSW_SRC" >&2
+  exit 1
+fi
+
+# Wrap a monitor source body in #ifdef <macro> ... #endif so it compiles to an
+# empty object on platforms that lack the feature. Idempotent and portable.
+add_guard() {
+  file=$1; macro=$2
+  if grep -q "WATCHER guard $macro" "$file" 2>/dev/null; then
+    echo -e "${GREEN}  ✓ self-guard $macro already present${NC}"; return 0
+  fi
+  awk -v m="$macro" '
+    { print }
+    $0 == "#include <libfswatch/libfswatch_config.h>" && !done {
+      print ""
+      print "#ifdef " m
+      done = 1
+    }
+    END { print ""; print "#endif  /* WATCHER guard " m " */" }
+  ' "$file" > "$file.tmp" && mv "$file.tmp" "$file"
+  echo -e "${GREEN}  ✓ self-guard $macro applied${NC}"
+}
+
+# --- Patch 1: string_utils.cpp null-format guard -----------------------------
+STRING_UTILS="$LIBFSW_SRC/c++/string/string_utils.cpp"
+if [ -f "$STRING_UTILS" ]; then
+  if grep -q "if (!format) return" "$STRING_UTILS"; then
+    echo -e "${GREEN}  ✓ string_utils null-format guard already present${NC}"
+  else
+    sed -i.bak 's|^      size_t current_buffer_size = 0;$|      if (!format) return string();\
+      size_t current_buffer_size = 0;|' "$STRING_UTILS"
+    rm -f "$STRING_UTILS.bak"
+    echo -e "${GREEN}  ✓ string_utils null-format guard applied${NC}"
+  fi
+else
+  echo -e "${YELLOW}  ⚠ string_utils.cpp not found, skipping${NC}"
+fi
+
+# --- Patch 2: self-guard the three non-self-guarding monitors ----------------
+add_guard "$LIBFSW_SRC/c++/fsevents_monitor.cpp" HAVE_FSEVENTS_FSEVENTSTREAMSETDISPATCHQUEUE
+add_guard "$LIBFSW_SRC/c++/inotify_monitor.cpp"  HAVE_INOTIFY_MONITOR
+add_guard "$LIBFSW_SRC/c++/fanotify_monitor.cpp" HAVE_FANOTIFY
+
+# --- Patch 3a: neuter the FSW_*LOG* macros (they expand `stderr` inline) ------
+LOG_H="$LIBFSW_SRC/c/libfswatch_log.h"
+if grep -q 'fsw_flogf(stderr' "$LOG_H" 2>/dev/null; then
+  perl -pi -e 's/^(#  define FSW_[A-Z]+\([^)]*\))\s+.*$/$1 ((void)0)/' "$LOG_H"
+  echo -e "${GREEN}  ✓ FSW_*LOG* macros neutered${NC}"
+else
+  echo -e "${GREEN}  ✓ FSW_*LOG* macros already neutered${NC}"
+fi
+
+# --- Patch 3b: empty the fsw_log* function bodies ----------------------------
+LOG_CPP="$LIBFSW_SRC/c/libfswatch_log.cpp"
+if grep -q 'watcher: logging neutered' "$LOG_CPP" 2>/dev/null; then
+  echo -e "${GREEN}  ✓ libfswatch_log.cpp already neutered${NC}"
+else
+  # Preserve the upstream licence header (everything before the first #include).
+  HEADER=$(awk '/^#include/{exit} {print}' "$LOG_CPP")
+  {
+    printf '%s\n' "$HEADER"
+    cat <<'EOF'
+/* watcher: logging neutered. libfswatch's diagnostics must not write to
+ * stdout/stderr from compiled code; watcher never enables verbose logging,
+ * so these are no-ops in normal use. See tools/patch_libfswatch.sh. */
+#include "libfswatch_log.h"
+
+void fsw_log(const char *) {}
+void fsw_flog(FILE *, const char *) {}
+void fsw_logf(const char *, ...) {}
+void fsw_flogf(FILE *, const char *, ...) {}
+void fsw_log_perror(const char *) {}
+void fsw_logf_perror(const char *, ...) {}
+EOF
+  } > "$LOG_CPP.tmp" && mv "$LOG_CPP.tmp" "$LOG_CPP"
+  echo -e "${GREEN}  ✓ libfswatch_log.cpp bodies emptied${NC}"
+fi
+
+# --- Patch 3c: drop the lone std::cerr in fsevents_monitor.cpp ---------------
+FSEVENTS="$LIBFSW_SRC/c++/fsevents_monitor.cpp"
+if grep -q 'std::cerr << "Warning: Failed to convert CFStringRef' "$FSEVENTS" 2>/dev/null; then
+  perl -ni -e 'print unless /std::cerr << "Warning: Failed to convert CFStringRef/' "$FSEVENTS"
+  echo -e "${GREEN}  ✓ fsevents_monitor.cpp std::cerr removed${NC}"
+else
+  echo -e "${GREEN}  ✓ fsevents_monitor.cpp std::cerr already removed${NC}"
+fi
+
+# --- Patch 3d: drop the Windows-only stderr/cerr diagnostics -----------------
+# These compile only on Windows (so they escape the POSIX checks); same policy
+# as 3a-3c. perror() is left as-is throughout -- R's compiled-code check does
+# not flag it. Each write is the lone statement in a braced block, so removing
+# the line leaves valid code (an empty else / a bare return false).
+WIN_DCE="$LIBFSW_SRC/c++/windows/win_directory_change_event.cpp"
+if grep -q 'cerr << _("File name unexpectedly empty' "$WIN_DCE" 2>/dev/null; then
+  perl -ni -e 'print unless /cerr << _\("File name unexpectedly empty/' "$WIN_DCE"
+  echo -e "${GREEN}  ✓ win_directory_change_event.cpp cerr removed${NC}"
+else
+  echo -e "${GREEN}  ✓ win_directory_change_event.cpp cerr already removed${NC}"
+fi
+
+WIN_MON="$LIBFSW_SRC/c++/windows_monitor.cpp"
+if grep -q 'fprintf(stderr, _("Invalid handle when opening' "$WIN_MON" 2>/dev/null; then
+  perl -ni -e 'print unless /fprintf\(stderr, _\("Invalid handle when opening/' "$WIN_MON"
+  echo -e "${GREEN}  ✓ windows_monitor.cpp fprintf(stderr) removed${NC}"
+else
+  echo -e "${GREEN}  ✓ windows_monitor.cpp fprintf(stderr) already removed${NC}"
+fi
diff --git a/tools/update_libfswatch.sh b/tools/update_libfswatch.sh
index dd67478..ac88e74 100755
--- a/tools/update_libfswatch.sh
+++ b/tools/update_libfswatch.sh
@@ -4,7 +4,11 @@
 # Usage: ./tools/update_libfswatch.sh [version/commit/tag]
 #
 # This script reproduces how to get the current vendored code from the
-# upstream libfswatch repository and applies local patches.
+# upstream libfswatch repository and applies local patches. It also
+# (re)generates the hand-maintained config header, the per-object compile
+# rules in src/Makevars.in / Makevars.win / Makevars.ucrt, and the POSIX
+# object list read by ./configure. No cmake or autotools artifacts are kept:
+# the bundled sources compile straight into the package shared object.
 
 set -e
 
@@ -17,8 +21,242 @@ NC='\033[0m' # No Color
 # Configuration
 FSWATCH_REPO="https://github.com/emcrisostomo/fswatch.git"
 FSWATCH_VERSION="${1:-master}"  # Default to master branch if no version specified
-WORK_DIR="$(pwd)/fswatch-update-tmp"
-TARGET_DIR="$(pwd)/src/fswatch"
+PKG_ROOT="$(pwd)"
+WORK_DIR="${PKG_ROOT}/fswatch-update-tmp"
+TARGET_DIR="${PKG_ROOT}/src/fswatch"
+
+# Bundled libfswatch object lists (single source of truth, paths use $(FSW)).
+# Keep in sync with ./configure (POSIX) and Makevars.win/.ucrt (Windows).
+COMMON_CORE='$(FSW)/c/cevent.o
+$(FSW)/c/libfswatch.o
+$(FSW)/c/libfswatch_log.o
+$(FSW)/c++/event.o
+$(FSW)/c++/filter.o
+$(FSW)/c++/libfswatch_exception.o
+$(FSW)/c++/monitor.o
+$(FSW)/c++/monitor_factory.o
+$(FSW)/c++/path_utils.o
+$(FSW)/c++/poll_monitor.o
+$(FSW)/c++/string/string_utils.o'
+
+POSIX_MONITORS='$(FSW)/c++/fsevents_monitor.o
+$(FSW)/c++/kqueue_monitor.o
+$(FSW)/c++/inotify_monitor.o
+$(FSW)/c++/fanotify_monitor.o
+$(FSW)/c++/fen_monitor.o'
+
+WINDOWS_MONITORS='$(FSW)/c++/windows_monitor.o
+$(FSW)/c++/windows/win_directory_change_event.o
+$(FSW)/c++/windows/win_error_message.o
+$(FSW)/c++/windows/win_handle.o
+$(FSW)/c++/windows/win_paths.o
+$(FSW)/c++/windows/win_strings.o'
+
+# Emit one explicit compile rule per object (object paths read from stdin).
+emit_rules() {
+  while IFS= read -r obj; do
+    [ -n "$obj" ] || continue
+    src="${obj%.o}.cpp"
+    printf '%s: %s\n\t$(CXX) $(ALL_CPPFLAGS) $(ALL_CXXFLAGS) -c %s -o $@\n' "$obj" "$src" "$src"
+  done
+}
+
+# Join an object list (stdin) into one trimmed space-separated line.
+join_objs() { tr '\n' ' ' | sed 's/ *$//'; }
+
+# Write the hand-maintained config header (replaces the cmake template).
+write_config_header() {
+  cat > "$1" <<'EOF'
+/* Hand-maintained replacement for the cmake/autotools-generated config header.
+ * Feature selection is keyed on compiler-predefined platform macros.
+ * Regenerated/owned by the watcher package — not by upstream tooling. */
+#ifndef LIBFSWATCH_CONFIG_H
+#define LIBFSWATCH_CONFIG_H
+
+/* C++17 guarantees these; used by libfswatch_map.hpp / libfswatch_set.hpp */
+#define HAVE_UNORDERED_MAP 1
+#define HAVE_UNORDERED_SET 1
+
+#if defined(__APPLE__)
+/* FSEvents + kqueue. The HAVE_MACOS_GE_* gates are *derived from the deployment
+ * target* (a compile-time "probe" of MAC_OS_X_VERSION_MIN_REQUIRED) rather than
+ * hard-set true: this stays correct for any floor R might use, costs nothing,
+ * and needs no configure machinery. Compare against the named MAC_OS_X_VERSION_*
+ * constants — their numeric encoding changed (1090 vs 101000) at 10.10. */
+#  include <AvailabilityMacros.h>
+#  define HAVE_FSEVENTS_FSEVENTSTREAMSETDISPATCHQUEUE 1
+#  define HAVE_SYS_EVENT_H 1
+#  define HAVE_STRUCT_STAT_ST_MTIMESPEC 1
+#  if MAC_OS_X_VERSION_MIN_REQUIRED >= MAC_OS_X_VERSION_10_5
+#    define HAVE_MACOS_GE_10_5 1
+#  endif
+#  if MAC_OS_X_VERSION_MIN_REQUIRED >= MAC_OS_X_VERSION_10_6
+#    define HAVE_MACOS_GE_10_6 1
+#  endif
+#  if MAC_OS_X_VERSION_MIN_REQUIRED >= MAC_OS_X_VERSION_10_7
+#    define HAVE_MACOS_GE_10_7 1
+#  endif
+#  if MAC_OS_X_VERSION_MIN_REQUIRED >= MAC_OS_X_VERSION_10_9
+#    define HAVE_MACOS_GE_10_9 1
+#  endif
+#  if MAC_OS_X_VERSION_MIN_REQUIRED >= MAC_OS_X_VERSION_10_10
+#    define HAVE_MACOS_GE_10_10 1
+#  endif
+#  if MAC_OS_X_VERSION_MIN_REQUIRED >= MAC_OS_X_VERSION_10_13
+#    define HAVE_MACOS_GE_10_13 1
+#  endif
+
+#elif defined(_WIN32)
+#  define HAVE_WINDOWS 1
+#  define HAVE_STRUCT_STAT_ST_MTIME 1
+
+#elif defined(__linux__)
+#  define HAVE_SYS_INOTIFY_H 1
+#  define HAVE_SYS_EPOLL_H 1
+#  define HAVE_SYS_EVENTFD_H 1
+#  define HAVE_INOTIFY_MONITOR 1
+#  define HAVE_STRUCT_STAT_ST_MTIME 1
+/* fanotify intentionally OFF: requires CAP_SYS_ADMIN/root and a large symbol surface. */
+
+#elif defined(__FreeBSD__) || defined(__OpenBSD__) || defined(__NetBSD__) || defined(__DragonFly__)
+#  define HAVE_SYS_EVENT_H 1
+#  define HAVE_STRUCT_STAT_ST_MTIMESPEC 1
+
+#elif defined(__sun)
+#  define HAVE_PORT_H 1
+#  define HAVE_STRUCT_STAT_ST_MTIME 1
+
+#else
+/* Generic POSIX fallback: stat()-based poll monitor only. */
+#  define HAVE_STRUCT_STAT_ST_MTIME 1
+#endif
+
+#endif /* LIBFSWATCH_CONFIG_H */
+EOF
+}
+
+# (Re)generate the POSIX object list and the three Makevars files.
+generate_build_files() {
+  printf '%s\n%s\n' "$COMMON_CORE" "$POSIX_MONITORS" > "$PKG_ROOT/tools/fsw_objects_posix.list"
+
+  # --- src/Makevars.in (POSIX; configure fills @cppflags@/@libs@/@fsw_objects@)
+  {
+    cat <<'EOF'
+# Generated by tools/update_libfswatch.sh -- do not edit by hand.
+#
+# Compile the bundled libfswatch sources directly into the package shared object
+# (no cmake, no static archive). configure substitutes the include flags, the
+# link flags, the bundled object list (empty when a system libfswatch is used)
+# and the C++ standard line (a CXX_STD request set only on R < 4.3 -- see
+# configure).
+#
+# PKG_CPPFLAGS carries the include path so it reaches BOTH the C package files
+# and the bundled C++ via $(ALL_CPPFLAGS).
+PKG_CPPFLAGS = @cppflags@
+PKG_CFLAGS = $(C_VISIBILITY)
+PKG_CXXFLAGS = $(CXX_VISIBILITY)
+PKG_LIBS = @libs@
+
+@cxx_std@
+
+# Top-level package sources (built by R's own suffix rules)
+P_OBJECTS = init.o watcher.o
+# Bundled libfswatch objects (empty when a system libfswatch is used)
+FSW_OBJECTS = @fsw_objects@
+
+OBJECTS = $(P_OBJECTS) $(FSW_OBJECTS)
+
+FSW = fswatch/libfswatch/src/libfswatch
+
+# `all:` MUST be the first target: an explicit object rule below would otherwise
+# become make's default goal when R CMD SHLIB invokes make with no target.
+all: $(SHLIB)
+
+$(SHLIB): $(OBJECTS)
+
+# --- Explicit compile rules for the bundled (subdirectory) sources -----------
+# One rule per object; recipe identical to R's own .cpp.o suffix rule. Each
+# names its source explicitly and uses only portable make variables, so any
+# POSIX make builds them (no automatic-variable source refs, no pattern rules,
+# no directory search, no file inclusion).
+EOF
+    printf '%s\n%s\n' "$COMMON_CORE" "$POSIX_MONITORS" | emit_rules
+    printf '\n.PHONY: all clean\nclean:\n\trm -f $(OBJECTS) $(SHLIB)\n'
+  } > "$PKG_ROOT/src/Makevars.in"
+
+  # --- src/Makevars.win (Rtools40, gcc 8.3, dual i386 + x64) ------------------
+  win_objs=$(printf '%s\n%s\n' "$COMMON_CORE" "$WINDOWS_MONITORS" | join_objs)
+  {
+    cat <<'EOF'
+# Generated by tools/update_libfswatch.sh -- do not edit by hand.
+#
+# Rtools40 (gcc 8.3), dual i386 + x64. Always compiles the bundled libfswatch
+# (no system-library path on Windows). std::filesystem is used in the common
+# core, so -lstdc++fs is required on gcc 8.x/9.x.
+#
+# CXX_STD stays static here: Rtools40 only ever serves R <= 4.1 (< 4.3), whose
+# default is below C++17, so requesting it is always needed and never trips the
+# CRAN "please drop specification" NOTE. (UCRT is conditional -- see
+# Makevars.ucrt.in / configure.ucrt.)
+PKG_CPPFLAGS = -Ifswatch/libfswatch/src
+PKG_CFLAGS = $(C_VISIBILITY)
+PKG_CXXFLAGS = $(CXX_VISIBILITY)
+PKG_LIBS = -pthread -lstdc++fs
+
+CXX_STD = CXX17
+
+P_OBJECTS = init.o watcher.o
+FSW = fswatch/libfswatch/src/libfswatch
+EOF
+    printf 'FSW_OBJECTS = %s\n' "$win_objs"
+    cat <<'EOF'
+
+OBJECTS = $(P_OBJECTS) $(FSW_OBJECTS)
+
+all: $(SHLIB)
+
+$(SHLIB): $(OBJECTS)
+
+EOF
+    printf '%s\n%s\n' "$COMMON_CORE" "$WINDOWS_MONITORS" | emit_rules
+    printf '\n.PHONY: all clean\nclean:\n\trm -f $(OBJECTS) $(SHLIB)\n'
+  } > "$PKG_ROOT/src/Makevars.win"
+
+  # --- src/Makevars.ucrt (Rtools42/43/44; std::filesystem in libstdc++) -------
+  {
+    cat <<'EOF'
+# Generated by tools/update_libfswatch.sh -- do not edit by hand.
+# Template: configure.ucrt fills in the C++ standard line to produce
+# src/Makevars.ucrt.
+#
+# Rtools42/43/44 (gcc 10/12/13). Identical to Makevars.win except that
+# std::filesystem is folded into libstdc++, so -lstdc++fs is not needed, and the
+# CXX_STD request is emitted only on R < 4.3 (R >= 4.3 defaults to C++17;
+# specifying it then trips a CRAN "please drop specification" NOTE).
+PKG_CPPFLAGS = -Ifswatch/libfswatch/src
+PKG_CFLAGS = $(C_VISIBILITY)
+PKG_CXXFLAGS = $(CXX_VISIBILITY)
+PKG_LIBS = -pthread
+
+@cxx_std@
+
+P_OBJECTS = init.o watcher.o
+FSW = fswatch/libfswatch/src/libfswatch
+EOF
+    printf 'FSW_OBJECTS = %s\n' "$win_objs"
+    cat <<'EOF'
+
+OBJECTS = $(P_OBJECTS) $(FSW_OBJECTS)
+
+all: $(SHLIB)
+
+$(SHLIB): $(OBJECTS)
+
+EOF
+    printf '%s\n%s\n' "$COMMON_CORE" "$WINDOWS_MONITORS" | emit_rules
+    printf '\n.PHONY: all clean\nclean:\n\trm -f $(OBJECTS) $(SHLIB)\n'
+  } > "$PKG_ROOT/src/Makevars.ucrt.in"
+}
 
 echo -e "${GREEN}=== LibFSWatch Update Script ===${NC}"
 echo "Repository: ${FSWATCH_REPO}"
@@ -63,45 +301,40 @@ echo -e "${YELLOW}Step 2: Extracting required files...${NC}"
 STAGING_DIR="${WORK_DIR}/staging"
 mkdir -p "${STAGING_DIR}"
 
-# Copy the files we need (excluding fswatch CLI tool, tests, and build infrastructure)
+# Copy the files we need (excluding fswatch CLI tool, tests, and all build
+# infrastructure — we compile in place, so no CMakeLists.txt is wanted).
 echo "Copying libfswatch source files..."
 cp -r libfswatch "${STAGING_DIR}/"
 
-# Copy top-level files needed for the build
-cp CMakeLists.txt "${STAGING_DIR}/"
+# Copy attribution files (required by DESCRIPTION cph entries / src/LICENSE.note)
 cp AUTHORS "${STAGING_DIR}/"
 cp AUTHORS.libfswatch "${STAGING_DIR}/"
 cp LICENSE-2.0.txt "${STAGING_DIR}/"
 cp README.md "${STAGING_DIR}/"
 
-# Remove unnecessary files from libfswatch
+# Remove docs, automake files, and every cmake/config artifact: we own the
+# config header and drive the build from the package Makevars.
 echo "Cleaning up unnecessary files..."
 rm -rf "${STAGING_DIR}/libfswatch/doc"
 find "${STAGING_DIR}" -name "Makefile.am" -delete
+rm -f "${STAGING_DIR}/libfswatch/CMakeLists.txt"
+rm -f "${STAGING_DIR}/libfswatch/src/libfswatch.pc.in"
+rm -f "${STAGING_DIR}/libfswatch/libfswatch_config.in"
 
 echo ""
 
-# Step 3: Apply patches specific to watcher package
+# Step 3: Apply patches and write the owned config header
 echo -e "${YELLOW}Step 3: Applying patches for watcher package...${NC}"
 
-# Patch: Avoid GCC -Wformat-truncation "null format string" warning in
-# string_utils.cpp by adding an explicit null check on the format argument
-# before the vsnprintf call. Surfaces in stricter CRAN/rhub Linux builds.
-echo "Applying string_utils.cpp null-format guard..."
-STRING_UTILS="${STAGING_DIR}/libfswatch/src/libfswatch/c++/string/string_utils.cpp"
-
-if [ -f "${STRING_UTILS}" ]; then
-  if ! grep -q "if (!format) return" "${STRING_UTILS}"; then
-    sed -i.bak 's|^      size_t current_buffer_size = 0;$|      if (!format) return string();\
-      size_t current_buffer_size = 0;|' "${STRING_UTILS}"
-    rm -f "${STRING_UTILS}.bak"
-    echo -e "${GREEN}  ✓ Null-format guard applied${NC}"
-  else
-    echo -e "${GREEN}  ✓ Null-format guard already present${NC}"
-  fi
-else
-  echo -e "${YELLOW}  ⚠ string_utils.cpp not found, skipping patch${NC}"
-fi
+LIBFSW_SRC="${STAGING_DIR}/libfswatch/src/libfswatch"
+
+echo "Writing hand-maintained libfswatch_config.h..."
+write_config_header "${LIBFSW_SRC}/libfswatch_config.h"
+echo -e "${GREEN}  ✓ config header written${NC}"
+
+# Apply all watcher source patches (string_utils guard, monitor self-guards,
+# logging neutering) idempotently to the staged tree.
+"${PKG_ROOT}/tools/patch_libfswatch.sh" "${LIBFSW_SRC}"
 
 echo ""
 
@@ -112,18 +345,27 @@ mv "${STAGING_DIR}" "${TARGET_DIR}"
 echo -e "${GREEN}Vendored code updated successfully!${NC}"
 echo ""
 
-# Step 5: Clean up
-echo -e "${YELLOW}Step 5: Cleaning up...${NC}"
-cd "$(dirname "${WORK_DIR}")"
+# Step 5: Regenerate build files (object list + Makevars)
+echo -e "${YELLOW}Step 5: Regenerating build files...${NC}"
+generate_build_files
+echo -e "${GREEN}  ✓ tools/fsw_objects_posix.list${NC}"
+echo -e "${GREEN}  ✓ src/Makevars.in, src/Makevars.win, src/Makevars.ucrt${NC}"
+echo ""
+
+# Step 6: Clean up
+echo -e "${YELLOW}Step 6: Cleaning up...${NC}"
+cd "${PKG_ROOT}"
 rm -rf "${WORK_DIR}"
 echo -e "${GREEN}Temporary files removed${NC}"
 echo ""
 
-# Step 6: Show summary
+# Step 7: Show summary
 echo -e "${GREEN}=== Update Complete ===${NC}"
 echo ""
 echo "Summary:"
 echo "  - Updated from commit: ${CURRENT_COMMIT}"
 echo "  - Updated from tag: ${CURRENT_TAG}"
-echo "  - Patches applied: string_utils.cpp null-format guard"
+echo "  - Owned libfswatch_config.h written"
+echo "  - Source patches applied via tools/patch_libfswatch.sh"
+echo "  - Regenerated Makevars + tools/fsw_objects_posix.list"
 echo ""