maint: add CI jobs to build and test a Windows wheel

.github/workflows/buildwheel.yml

@@ -63,3 +63,58 @@ jobs:
       - run: venv/bin/pip install -U pip
       - run: venv/bin/pip install --find-links wheelhouse python_flint
       - run: venv/bin/python test/test.py
+
+  build_windows:
+    #
+    # Test experimental Windows support. These wheels do not yet work due to
+    #
+    #    https://github.com/fredrik-johansson/python-flint/issues/10
+    #
+    # This job tests that building the wheel is possible with mingw-w64 under msys2.
+    #
+    name: Build Windows wheel
+    runs-on: windows-2019
+
+    steps:
+      - uses: actions/checkout@v3
+      - uses: actions/setup-python@v4
+        with:
+          python-version: '3.10'
+      - uses: msys2/setup-msys2@v2
+        with:
+          msystem: mingw64
+
+      - run: python -c 'import sys; print(sys.executable)'
+
+      - run: msys2 -c 'uname -a'
+
+      - run: msys2 -c 'bin/build_mingw64_wheel.sh'
+        env:
+          # This is where setup-python puts Python. We want the MSVC-built
+          # Python rather than an MSYS2 Python.
+          PYTHONDIR: '/c/hostedtoolcache/windows/Python/3.10.8/x64'
+
+      - uses: actions/upload-artifact@v3
+        with:
+          path: wheelhouse/*.whl
+
+  test_windows:
+    #
+    # For now this job is expected to fail.
+    #
+    needs: build_windows
+    name: Test Windows wheel
+    runs-on: windows-2019
+
+    steps:
+      - uses: actions/checkout@v3
+      - uses: actions/setup-python@v4
+        with:
+          python-version: '3.10'
+      - uses: actions/download-artifact@v3
+        with:
+          name: artifact
+          path: wheelhouse
+      - run: python -m pip install -U pip
+      - run: pip install --find-links wheelhouse python_flint
+      - run: python test/test.py

bin/build_mingw64_wheel.sh

@@ -0,0 +1,84 @@
+#!/bin/bash
+#
+# make_wheels.sh
+#
+# Build relocatable Windows wheel for python_flint using the mingw-w64
+# toolchain in the MSYS2 enironment.
+#
+# - First install Python
+#
+#       https://www.python.org/ftp/python/3.10.8/python-3.10.8-amd64.exe
+#
+# - Then checkout the code:
+#
+#       $ git clone https://github.com/fredrik-johansson/python-flint/issues/1
+#
+# - Then install msys2
+#
+#       https://repo.msys2.org/distrib/x86_64/msys2-x86_64-20221028.exe
+#
+# - Then open msys2, cd into the checked out repo. Make sure setup.py says
+#
+#       libraries = ["arb", "flint", "mpfr", "gmp"]
+#
+# - Set the environment variable to the directory containing the installed
+#   Python that we want to build a wheel for i.e. the one installed from
+#   python.org. If python was on PATH then it would be
+#
+#        PYTHONDIR=`dirname $(which python)`
+#
+# - Then run this script.
+
+set -o errexit
+
+#
+# In CI this environment variable needs to be set to the directory containing
+# the python.org installation of Python. If Python is installed in msys2 then
+# it is also necesary to set this environment variable so that it picks up the
+# right installation of Python i.e. the one that we want to build a wheel for.
+#
+if [[ -z "$PYTHONDIR" ]]; then
+  PYTHONDIR=`dirname $(which python)`
+fi
+PYTHON=$PYTHONDIR/python
+
+WHEELNAME=python_flint-0.3.0-cp310-cp310-win_amd64.whl
+
+$PYTHON -c 'print("hello world")'
+
+echo $PYTHONDIR
+ls $PYTHONDIR
+ls $PYTHONDIR/libs
+
+# Install the mingw-w64 toolchain
+pacman -S --noconfirm mingw-w64-x86_64-gcc m4 make mingw-w64-x86_64-tools-git
+
+# This takes ~1hr
+bin/build_dependencies_unix.sh
+
+# Add the libpython310.a file to Python installation
+cd $PYTHONDIR
+  gendef python310.dll
+  dlltool --dllname python310.dll --def python310.def --output-lib libpython310.a
+  mv libpython310.a libs
+cd -
+
+# Make a virtual environment to install the build dependencies
+$PYTHON -m venv .local/venv
+source .local/venv/Scripts/activate
+pip install numpy cython wheel delvewheel
+
+# Build the wheel
+C_INCLUDE_PATH=.local/include/ LIBRARY_PATH=.local/lib/ python setup.py build_ext -cmingw32 -f bdist_wheel
+
+# Make the wheel relocatable
+delvewheel repair dist/python_flint-0.3.0-cp310-cp310-win_amd64.whl \
+        --add-path .local/bin:.local/lib/ \
+        '--no-mangle=libflint-17.dll;libarb-2.dll;libgmp-10.dll;libmpfr-6.dll;libgcc_s_seh-1.dll'
+
+# Make a virtual enironment to test the wheel
+#
+# $PYTHON -m venv test_env
+# source test_env/Scripts/activate
+# pip install wheelhouse/$WHEELNAME
+# python -c 'import flint; print(flint.fmpz(2) + 2)'  # 2 + 2 = 4?

setup.py

@@ -9,7 +9,7 @@
 from distutils.sysconfig import get_config_vars
 
 if sys.platform == 'win32':
-    libraries = ["arb", "flint", "mpir", "mpfr", "pthreads"]
+    libraries = ["arb", "flint", "mpfr", "gmp"]
 else:
     libraries = ["arb", "flint"]
     (opt,) = get_config_vars('OPT')