BLD: Try installing older Cython for windows free threading build

pyproject.toml

@@ -148,7 +148,7 @@ setup = ['--vsenv'] # For Windows
 
 [tool.cibuildwheel]
 skip = "cp36-* cp37-* cp38-* cp39-* pp* *_i686 *_ppc64le *_s390x"
-build-verbosity = "3"
+build-verbosity = 3
 environment = {LDFLAGS="-Wl,--strip-all"}
 test-requires = "hypothesis>=6.84.0 pytest>=7.3.2 pytest-xdist>=3.4.0"
 test-command = """
@@ -160,6 +160,7 @@ free-threaded-support = true
 before-build = "PACKAGE_DIR={package} bash {package}/scripts/cibw_before_build.sh"
 
 [tool.cibuildwheel.windows]
+environment = {}
 before-build = "pip install delvewheel && bash {package}/scripts/cibw_before_build_windows.sh"
 before-test = "bash {package}/scripts/cibw_before_test_windows.sh"
 test-command = """

scripts/cibw_before_build_windows.sh

@@ -5,10 +5,11 @@ for file in $PACKAGE_DIR/LICENSES/*; do
 done
 
 # TODO: Delete when there's a PyPI Cython release that supports free-threaded Python 3.13
-# and a NumPy Windows wheel for the free-threaded build on PyPI.
 FREE_THREADED_BUILD="$(python -c"import sysconfig; print(bool(sysconfig.get_config_var('Py_GIL_DISABLED')))")"
 if [[ $FREE_THREADED_BUILD == "True" ]]; then
     python -m pip install -U pip
-    python -m pip install -i https://pypi.anaconda.org/scientific-python-nightly-wheels/simple numpy cython
-    python -m pip install ninja meson-python versioneer[toml]
+    # python -m pip install -i https://pypi.anaconda.org/scientific-python-nightly-wheels/simple cython
+    # TODO: Remove below and uncomment above once https://github.com/cython/cython/pull/6717 no longer breaks tests
+    python -m pip install git+https://github.com/cython/cython.git@3276b588720a053c78488e5de788605950f4b136
+    python -m pip install ninja meson-python versioneer[toml] numpy
 fi