Improvements to the build of wheels for Linux.

- Set the flag `-fno-math-errno` so that the `errno` flag is not any longer being set when math functions are called.
- Exclude using Cython version `0.29.26` for building Python wheels as it fails building wheels for PyPy38.

python/build-wheels.sh

@@ -10,7 +10,7 @@ for PYBIN in /opt/python/*/bin; do
     # Skip deprecated or unsupported versions
     if "${PYBIN}/python" -c "import sys;sys.stdout.write(str(sys.version_info < (${PYTHON_MAX_VERSION})))" | grep -q 'True'; then
         "${PYBIN}/pip" install cmake
-        "${PYBIN}/cmake" -DCMAKE_C_FLAGS_RELEASE="-g -O2 -DNDEBUG" -DCMAKE_CXX_FLAGS_RELEASE="-g -O2 -DNDEBUG" -DCMAKE_BUILD_TYPE=Release ..
+        "${PYBIN}/cmake" -DCMAKE_C_FLAGS_RELEASE="-g -O2 -DNDEBUG -fno-math-errno" -DCMAKE_CXX_FLAGS_RELEASE="-g -O2 -DNDEBUG -fno-math-errno" -DCMAKE_BUILD_TYPE=Release ..
         # Only build libJSBSim because that's all we need for Python wheels.
         "${PYBIN}/cmake" --build . --target libJSBSim -- -j2
         break
@@ -23,7 +23,7 @@ cd python
 for PYBIN in /opt/python/*/bin; do
     # Skip deprecated or unsupported versions
     if "${PYBIN}/python" -c "import sys;sys.stdout.write(str(sys.version_info < (${PYTHON_MAX_VERSION})))" | grep -q 'True'; then
-        "${PYBIN}/pip" install 'cython<=0.29.25' numpy
+        "${PYBIN}/pip" install 'cython!=0.29.26' numpy  # Exclude Cython version 0.29.26 as it fails building for PyPy38
         "${PYBIN}/cython" --cplus jsbsim.pyx -o jsbsim.cxx
         "${PYBIN}/python" setup.py bdist_wheel --build-number=$GITHUB_RUN_NUMBER
     fi