CI: re-enable the windows msys2 build (1.4-maint)

.github/workflows/windows.yml

@@ -3,8 +3,9 @@ on: [push, pull_request]
 
 jobs:
   msys2-ucrt64:
-    if: false  # build is broken, thus disabled, see #8264
+    if: true  # can be used to temporarily disable the build
     runs-on: windows-latest
+    timeout-minutes: 90
     defaults:
       run:
         shell: msys2 {0}
@@ -18,11 +19,20 @@ jobs:
           update: true
       - name: Install dependencies
         run: ./scripts/msys2-install-deps
+      - name: Build python venv
+        run: |
+          # msys2's python is externally managed (PEP 668), so pip-installed packages go into a venv.
+          # --system-site-packages: use the python packages installed via pacman.
+          python -m venv --system-site-packages env
+          . env/bin/activate
+          pip install pyinstaller==6.22.3
       - name: Build
-        run: ./scripts/msys2-build
+        run: |
+          . env/bin/activate
+          ./scripts/msys2-build
       - name: Test
         run: ./dist/borg.exe -V
-      - uses: actions/upload-artifact@v3
+      - uses: actions/upload-artifact@v4
         with:
           name: borg-windows
           path: dist/borg.exe

scripts/msys2-build

@@ -1,8 +1,8 @@
 #!/bin/bash
 
 # build borg.exe
-SETUPTOOLS_USE_DISTUTILS=stdlib pip install -e .
+pip install -e .
 pyinstaller -y scripts/borg.exe.spec
 
 # build sdist and wheel in dist/...
-SETUPTOOLS_USE_DISTUTILS=stdlib python -m build
+python -m build

scripts/msys2-install-deps

@@ -1,4 +1,3 @@
 #!/bin/bash
 
 pacman -S --needed --noconfirm git mingw-w64-ucrt-x86_64-{toolchain,pkgconf,zstd,lz4,xxhash,openssl,python,cython,python-setuptools,python-wheel,python-build,python-pkgconfig,python-packaging,python-msgpack,python-pip}
-pip install pyinstaller==6.3.0