.github/workflows/dist.yml: Get generic_backend.pxd from Sage source tree for now

Author: Matthias Koeppe

.github/workflows/dist.yml

@@ -67,7 +67,7 @@ jobs:
       # https://cibuildwheel.readthedocs.io/en/stable/options/#requires-python
       CIBW_PROJECT_REQUIRES_PYTHON: ">=3.9"
       # Environment during wheel build
-      CIBW_ENVIRONMENT: "PATH=$(pwd)/local/bin:$PATH CPATH=$(pwd)/local/include:$CPATH LIBRARY_PATH=$(pwd)/local/lib:$LIBRARY_PATH LD_LIBRARY_PATH=$(pwd)/local/lib:$LD_LIBRARY_PATH PKG_CONFIG_PATH=$(pwd)/local/share/pkgconfig:$PKG_CONFIG_PATH ACLOCAL_PATH=/usr/share/aclocal"
+      CIBW_ENVIRONMENT: "PATH=$(pwd)/local/bin:$PATH CPATH=$(pwd)/local/include:$CPATH LIBRARY_PATH=$(pwd)/local/lib:$LIBRARY_PATH LD_LIBRARY_PATH=$(pwd)/local/lib:$LD_LIBRARY_PATH PKG_CONFIG_PATH=$(pwd)/local/share/pkgconfig:$PKG_CONFIG_PATH ACLOCAL_PATH=/usr/share/aclocal PYTHONPATH=$(pwd)/src"
       # Use 'build', not 'pip wheel'
       CIBW_BUILD_FRONTEND: build
     steps: