Compilation of python for foreign target platform problem.

Host arch is x86_64, target arch is arm (arm32).

Configuration is (target arch part):

        (cd build-python && \
        DESTDIR=${SYSROOT} \
        PKG_CONFIG=true \
        LIBFFI_INCLUDEDIR= \
        PATH=${CURDIR}/host-python-home/bin:$$PATH \
        PYTHONHOME=${CURDIR}/host-python-home/lib \
        PYTHONPATH=${CURDIR}/host-python-home/lib/python3.5 \
        ../cpython/configure \
          --host=${TARGET_CROSS} \
          --build=${BUILD_M_ARCH}-unknown-linux-gnu \
          --prefix=/usr \
          --sysconfdir=/etc \
          --localstatedir=/var \
          --enable-shared \
          --disable-ipv6 \
          --with-system-ffi \
          --with-system-expat \
          --without-ensurepip \
          --cache-file=config.cache\
        )
        sed -e 's/#define HAVE_ATTRIBUTE_FORMAT_PARSETUPLE 1/#undef HAVE_ATTRIBUTE_FORMAT_PARSETUPLE/' -i build-python/pyconfig.h
        sed -e '/^PGEN=/ s|=.*$$|=\t\t${CURDIR}/build-python-native/Parser/pgen|' -e '/^LDFLAGS=/ s|=.*$$|=\t\t-L.|' -e '/^\$$(PGEN):/,+1d' -e '/^LIBFFI_INCLUDEDIR=/ s|=.*$$|=|' -i build-python/Makefile

Problem: option -I/usr/include passed to compiler during modules compilation. This lead to fails, due to target platform is different from host.

Suggested patch resolve the issue for me.

BTW, pass -I/usr/include is useless even for native builds.