Created attachment 183886 [details]
fix "cc: error: unsupported option '-print-multi-os-directory'"

If option UNSET: LIBFFI    Use libffi from ports instead of bundled version
...
LD_LIBRARY_PATH=/tmp/ports/usr/ports/lang/python35/work/Python-3.5.3 ./python -E -S -m sysconfig --generate-posix-vars ; if test $? -ne 0 ; then  echo "generate-posix-vars failed" ;  rm -f ./pybuilddir.txt ;  exit 1 ;  fi
cc -c -fPIC -Wno-unused-result -Wsign-compare -Wunreachable-code -DNDEBUG -O2 -msse2 -msse3 -mssse3 -msse4.1 -pipe  -Werror=declaration-after-statement   -I. -I./Include -I/usr/local/include -I/usr/local/include -fPIC -DPy_BUILD_CORE -o Modules/_math.o Modules/_math.c
/tmp/ports/usr/ports/lang/python35/work/Python-3.5.3/Modules/socketmodule.c:5459:5: warning: code will never be executed [-Wunreachable-code]
    PyErr_SetString(PyExc_RuntimeError, "invalid handling of inet_ntop");
    ^~~~~~~~~~~~~~~
1 warning generated.
cc: error: unsupported option '-print-multi-os-directory'
cc: error: no input files
/tmp/ports/usr/ports/lang/python35/work/Python-3.5.3/Modules/_ctypes/libffi/src/x86/ffi64.c:224:16: warning: comparison of integers of different signs: 'int' and 'size_t'
      (aka 'unsigned long') [-Wsign-compare]
        for (i = 0; i < words; i++)
                    ~ ^ ~~~~~
/tmp/ports/usr/ports/lang/python35/work/Python-3.5.3/Modules/_ctypes/libffi/src/x86/ffi64.c:245:20: warning: comparison of integers of different signs: 'int' and 'size_t'
      (aka 'unsigned long') [-Wsign-compare]
            for (i = 0; i < num; i++)
                        ~ ^ ~~~
...