py-libxml2, py-cython: need to either blacklist gcc-4* or patch out -Wno-unused-result

[barracuda156]

gcc-4.2 does not understand this flag, and the build fails.

creating build/temp.macosx-10.6-ppc-cpython-310
/opt/local/var/macports/build/_opt_local_var_macports_sources_rsync.macports.org_macports_release_tarballs_ports_python_py-libxml2/py310-libxml2/work/compwrap/cc/usr/bin/gcc-4.2 -Wno-unused-result -Wsign-compare -fno-common -dynamic -DNDEBUG -g -fwrapv -O3 -Wall -pipe -Os -arch ppc -isysroot/ -D_REENTRANT=1 -I/opt/local/include/libxml2 -I/opt/local/Library/Frameworks/Python.framework/Versions/3.10/include/python3.10 -c libxml.c -o build/temp.macosx-10.6-ppc-cpython-310/libxml.o
cc1: error: unrecognized command line option "-Wno-unused-result"
error: command '/opt/local/var/macports/build/_opt_local_var_macports_sources_rsync.macports.org_macports_release_tarballs_ports_python_py-libxml2/py310-libxml2/work/compwrap/cc/usr/bin/gcc-4.2' failed with exit code 1
Command failed:  cd "/opt/local/var/macports/build/_opt_local_var_macports_sources_rsync.macports.org_macports_release_tarballs_ports_python_py-libxml2/py310-libxml2/work/libxml2-2.9.14/python" && /opt/local/Library/Frameworks/Python.framework/Versions/3.10/bin/python3.10 setup.py --no-user-cfg build -j4 
Exit code: 1
Error: Failed to build py310-libxml2: command execution failed

Same for py-cython:

/opt/local/var/macports/build/_opt_local_var_macports_sources_rsync.macports.org_macports_release_tarballs_ports_python_py-cython/py310-cython/work/compwrap/cc/usr/bin/gcc-4.2 -Wno-unused-result -Wsign-compare -fno-common -dynamic -DNDEBUG -g -fwrapv -O3 -Wall -pipe -Os -m64 -arch ppc -arch ppc64 -isysroot/ -I/opt/local/Library/Frameworks/Python.framework/Versions/3.10/include/python3.10 -c /opt/local/var/macports/build/_opt_local_var_macports_sources_rsync.macports.org_macports_release_tarballs_ports_python_py-cython/py310-cython/work/Cython-0.29.29/Cython/Plex/Scanners.c -o build/temp.macosx-10.5-ppc64-cpython-310/opt/local/var/macports/build/_opt_local_var_macports_sources_rsync.macports.org_macports_release_tarballs_ports_python_py-cython/py310-cython/work/Cython-0.29.29/Cython/Plex/Scanners.o
cc1: error: unrecognized command line option "-Wno-unused-result"
cc1: error: unrecognized command line option "-Wno-unused-result"
fatal error: lipo: can't open input file: /opt/local/var/macports/build/_opt_local_var_macports_sources_rsync.macports.org_macports_release_tarballs_ports_python_py-cython/py310-cython/work/.tmp/cc6ta5kY.out (No such file or directory)
error: command '/opt/local/var/macports/build/_opt_local_var_macports_sources_rsync.macports.org_macports_release_tarballs_ports_python_py-cython/py310-cython/work/compwrap/cc/usr/bin/gcc-4.2' failed with exit code 1
* Getting dependencies for wheel...
* Building wheel...

ERROR Backend subproccess exited when trying to invoke build_wheel

[barracuda156]

It fails for x86_64 too:

creating build/lib.macosx-10.6-x86_64-cpython-310
copying libxml2.py -> build/lib.macosx-10.6-x86_64-cpython-310
copying drv_libxml2.py -> build/lib.macosx-10.6-x86_64-cpython-310
running build_ext
building 'libxml2mod' extension
creating build/temp.macosx-10.6-x86_64-cpython-310
/opt/x86_64/var/macports/build/_opt_x86_64_var_macports_sources_rsync.macports.org_macports_release_tarballs_ports_python_py-libxml2/py310-libxml2/work/compwrap/cc/usr/bin/gcc-4.2 -Wno-unused-result -Wsign-compare -fno-common -dynamic -DNDEBUG -g -fwrapv -O3 -Wall -pipe -Os -arch x86_64 -isysroot/ -D_REENTRANT=1 -I/opt/x86_64/include/libxml2 -I/opt/x86_64/Library/Frameworks/Python.framework/Versions/3.10/include/python3.10 -c libxml.c -o build/temp.macosx-10.6-x86_64-cpython-310/libxml.o
cc1: error: unrecognized command line option "-Wno-unused-result"
error: command '/opt/x86_64/var/macports/build/_opt_x86_64_var_macports_sources_rsync.macports.org_macports_release_tarballs_ports_python_py-libxml2/py310-libxml2/work/compwrap/cc/usr/bin/gcc-4.2' failed with exit code 1
Command failed:  cd "/opt/x86_64/var/macports/build/_opt_x86_64_var_macports_sources_rsync.macports.org_macports_release_tarballs_ports_python_py-libxml2/py310-libxml2/work/libxml2-2.9.14/python" && /opt/x86_64/Library/Frameworks/Python.framework/Versions/3.10/bin/python3.10 setup.py --no-user-cfg build -j4 
Exit code: 1
Error: Failed to build py310-libxml2: command execution failed
Error: See /opt/x86_64/var/macports/logs/_opt_x86_64_var_macports_sources_rsync.macports.org_macports_release_tarballs_ports_python_py-libxml2/py310-libxml2/main.log for details.