From 56729c53f58fe9e17d69951983ad621005753fbd Mon Sep 17 00:00:00 2001
From: Luca Toniolo <10792599+grandixximo@users.noreply.github.com>
Date: Mon, 26 Oct 2026 17:54:35 +1100
Subject: [PATCH] configure: fall back to the default scheme for SITEPY

The 2.9 merge 2511cf1174 took the 2.9 SITEPY line, which falls back
to a hardcoded /usr/lib/python3/dist-packages when neither the
deb_system nor the rpm_prefix scheme exists. On Gentoo that path is
not on sys.path, so the linuxcnc module is not found. Master used to
fall back to the interpreter's default scheme; restore that.

Reported by Alec Ari (NTULINUX).

Fixes #4717
---
 src/configure.ac | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/configure.ac b/src/configure.ac
index 0ba74c1426a..ab8b4a08f53 100644
--- a/src/configure.ac
+++ b/src/configure.ac
@@ -1742,7 +1742,7 @@ AC_MSG_RESULT([$PYTHON_TK_VERSION])
 fi
 
 AC_MSG_CHECKING(for site-package location)
-SITEPY=`$PYTHON -c "import sysconfig; s=sysconfig.get_scheme_names(); print(next((sysconfig.get_path('platlib', m) for m in ('deb_system', 'rpm_prefix') if m in s), '/usr/lib/python3/dist-packages'))"`
+SITEPY=`$PYTHON -c "import sysconfig; s=sysconfig.get_scheme_names(); print(next((sysconfig.get_path('platlib', m) for m in ('deb_system', 'rpm_prefix') if m in s), sysconfig.get_path('platlib')))"`
 AC_MSG_RESULT($SITEPY)
 
 if test "$BUILD_GUI" = "yes"; then