m4: Use python-config if available to fix Python 3 support on newer distros
m4: Use python-config if available to fix Python 3 support on newer distros

Tatsh/libplist,Tatsh/libplist,Tatsh/libplist,libimobiledevice-win32/libplist,libimobiledevice/libplist,libimobiledevice-win32/libplist,libimobiledevice/libplist,libimobiledevice-win32/libplist,libimobiledevice/libplist,Tatsh/libplist,libimobiledevice-win32/libplist