The recent python build fix for MAC removed hardcoded paths to
clone/libs-extern-sys/python/unxlngi6.pro/misc/build/python-inst
The result is that we need to set PYTHONHOME. Also we need to add
python/lib-dynload into PYTHONPATH
This commit also cleans up the condition for SYSTEM_TRANSLATE_TOOLKIT.
It removed the ugly "$(AUGMENT_LIBRARY_PATH) $(WRAPCMD)" when the system
toolkit is used.