MAINT: improve Windows-specific code, pin delvewheel

Cleans up a Windows workaround in `cibw_test_commmand.sh` that is no
longer needed.

Author: rgommers

requirements/delvewheel_requirements.txt

@@ -0,0 +1 @@
+delvewheel==1.10.1 ; sys_platform == 'win32'

tools/wheels/cibw_before_build.sh

@@ -25,7 +25,7 @@ elif [ -z $INSTALL_OPENBLAS ]; then
     export INSTALL_OPENBLAS=true
 fi
 
-# Install OpenBLAS from scipy-openblas64
+# Install OpenBLAS from scipy-openblas32|64
 if [[ "$INSTALL_OPENBLAS" = "true" ]] ; then
     # By default, use scipy-openblas64
     # On 32-bit platforms and on win-arm64, use scipy-openblas32
@@ -42,10 +42,20 @@ if [[ "$INSTALL_OPENBLAS" = "true" ]] ; then
     mkdir -p $PKG_CONFIG_PATH
     python -m pip install -r $PROJECT_DIR/requirements/openblas_requirements.txt
     python -c "import scipy_${OPENBLAS}; print(scipy_${OPENBLAS}.get_pkg_config())" > $PKG_CONFIG_PATH/scipy-openblas.pc
+
+    # Copy scipy-openblas DLL's to a fixed location so we can point delvewheel
+    # at it in `repair_windows.sh` (needed only on Windows because of the lack
+    # of RPATH support).
+    if [[ $RUNNER_OS == "Windows" ]]; then
+        python <<EOF
+import os, scipy_${OPENBLAS}, shutil
+srcdir = os.path.join(os.path.dirname(scipy_${OPENBLAS}.__file__), "lib")
+shutil.copytree(srcdir, os.path.join("$PKG_CONFIG_PATH", "lib"))
+EOF
+    fi
 fi
 
-# cibuildwheel doesn't install delvewheel by default (it does install
-# auditwheel on Linux and delocate on macOS)
+# cibuildwheel doesn't install delvewheel by default
 if [[ $RUNNER_OS == "Windows" ]]; then
-    python -m pip install delvewheel
+    python -m pip install -r $PROJECT_DIR/requirements/delvewheel_requirements.txt
 fi

tools/wheels/cibw_test_command.sh

@@ -6,11 +6,6 @@ PROJECT_DIR="$1"
 
 python -c "import numpy; numpy.show_config()"
 
-if [[ $RUNNER_OS == "Windows" ]]; then
-    # see gh-20391
-    PY_DIR=$(python -c "import sys; print(sys.prefix)")
-    mkdir $PY_DIR/libs
-fi
 if [[ $RUNNER_OS == "macOS"  && $RUNNER_ARCH == "X64" ]]; then
   # Not clear why this is needed but it seems on x86_64 this is not the default
   # and without it f2py tests fail
@@ -19,7 +14,6 @@ if [[ $RUNNER_OS == "macOS"  && $RUNNER_ARCH == "X64" ]]; then
   # in f2py tests
   export LIBRARY_PATH="$LIBRARY_PATH:/Library/Developer/CommandLineTools/SDKs/MacOSX.sdk/usr/lib"
 elif [[ $RUNNER_OS == "Windows" && $IS_32_BIT == true ]] ; 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
 fi

tools/wheels/repair_windows.sh

@@ -6,6 +6,6 @@ DEST_DIR="$2"
 cwd=$PWD
 cd $DEST_DIR
 
-# the libopenblas.dll is placed into this directory in the cibw_before_build
-# script.
+# The libopenblas_scipy DLL and the other DLLs it may need are placed into this
+# directory in `cibw_before_build.sh`.
 delvewheel repair --add-path $cwd/.openblas/lib -w $DEST_DIR $WHEEL