BLD: build wheels for 32-bit Python on Windows, using MSVC

This doesn't include OpenBLAS, I haven't tried that - too much
effort right now and it doesn't seem critical. Easier to revisit
once OpenBLAS is more easily installable as a wheel.

xref numpygh-23717

[skip circle] [skip cirrus] [skip azp]

Author: rgommers

.github/workflows/wheels.yml

@@ -76,6 +76,7 @@ jobs:
           - [ubuntu-20.04, musllinux_x86_64]
           - [macos-12, macosx_x86_64]
           - [windows-2019, win_amd64]
+          - [windows-2019, win32]
         python: ["cp39", "cp310", "cp311", "cp312"]  # "pp39"
         exclude:
           # Don't build PyPy 32-bit windows
@@ -98,6 +99,12 @@ jobs:
           # https://github.com/actions/checkout/issues/338
           fetch-depth: 0
 
+      - name: Setup MSVC (32-bit)
+        if: ${{ matrix.buildplat[1] == 'win32' }}
+        uses: bus1/cabuild/action/msdevshell@e22aba57d6e74891d059d66501b6b5aed8123c4d  # v1
+        with:
+          architecture: 'x86'
+
       - name: pkg-config-for-win
         run: |
           choco install -y --checksum 6004DF17818F5A6DBF19CB335CC92702 pkgconfiglite

pyproject.toml

@@ -150,7 +150,7 @@ tracker = "https://github.com/numpy/numpy/issues"
 # Note: the below skip command doesn't do much currently, the platforms to
 # build wheels for in CI are controlled in `.github/workflows/wheels.yml` and
 # `tools/ci/cirrus_wheels.yml`.
-skip = "cp36-* cp37-* cp-38* pp37-* *-manylinux_i686 *_ppc64le *_s390x *-musllinux_aarch64 *-win32"
+skip = "cp36-* cp37-* cp-38* pp37-* *-manylinux_i686 *_ppc64le *_s390x *-musllinux_aarch64"
 build-verbosity = "3"
 before-build = "bash {project}/tools/wheels/cibw_before_build.sh {project}"
 # meson has a hard dependency on ninja, and we need meson to build
@@ -179,17 +179,15 @@ test-skip = "*_universal2:arm64"
 environment = {CFLAGS="-fno-strict-aliasing -DBLAS_SYMBOL_SUFFIX=64_ -DHAVE_BLAS_ILP64", CXXFLAGS="-DBLAS_SYMBOL_SUFFIX=64_ -DHAVE_BLAS_ILP64", NPY_USE_BLAS_ILP64="1", CC="clang", CXX = "clang++", RUNNER_OS="macOS"}
 
 [tool.cibuildwheel.windows]
-archs = ['AMD64']
 environment = {NPY_USE_BLAS_ILP64="1", CFLAGS="-DBLAS_SYMBOL_SUFFIX=64_ -DHAVE_BLAS_ILP64", CXXFLAGS="-DBLAS_SYMBOL_SUFFIX=64_ -DHAVE_BLAS_ILP64", LDFLAGS="", PKG_CONFIG_PATH="C:/opt/64/lib/pkgconfig"}
 config-settings = "setup-args=--vsenv"
 repair-wheel-command = "bash ./tools/wheels/repair_windows.sh {wheel} {dest_dir}"
 
-#[[tool.cibuildwheel.overrides]]
-# Note: 32-bit Python wheel builds are skipped right now; probably needs
-# --native-file to build due to `arch != pyarch` check in Meson's `python` dependency
-# Note: uses 32-bit rather than 64-bit OpenBLAS
-#select = "*-win32"
-#environment = CFLAGS="-m32", LDFLAGS="-m32", PKG_CONFIG_PATH="/opt/32/lib/pkgconfig"}
+[[tool.cibuildwheel.overrides]]
+select = "*-win32"
+environment = {PKG_CONFIG_PATH="/opt/32/lib/pkgconfig"}
+config-settings = "setup-args=--vsenv setup-args=-Dallow-noblas=true"
+repair-wheel-command = ""
 
 [tool.spin]
 package = 'numpy'

tools/wheels/cibw_test_command.sh

@@ -18,6 +18,10 @@ if [[ $RUNNER_OS == "macOS"  && $RUNNER_ARCH == "X64" ]]; then
   # Needed so gfortran (not clang) can find system libraries like libm (-lm)
   # in f2py tests
   export LIBRARY_PATH="$LIBRARY_PATH:/Library/Developer/CommandLineTools/SDKs/MacOSX.sdk/usr/lib"
+elif [ IS_32_BIT ] ; then
+  echo "Skip OpenBLAS version check for 32-bit Windows, no OpenBLAS used"
+  # Avoid this in GHA: "ERROR: Found GNU link.exe instead of MSVC link.exe"
+  rm /c/Program\ Files/Git/usr/bin/link.EXE
 else
   # For some reason the macos-x86_64 runner does not work with threadpoolctl
   # Skip this check there

tools/wheels/repair_windows.sh

@@ -17,7 +17,7 @@ pushd numpy*
 # building with mingw.
 # We therefore find each PYD in the directory structure and strip them.
 
-for f in $(find ./scipy* -name '*.pyd'); do strip $f; done
+for f in $(find ./numpy* -name '*.pyd'); do strip $f; done
 
 
 # now repack the wheel and overwrite the original