Still wondering how to get Xcode to use my own flex 2.6.4 / bison 3.7 rather than the built ins, which are out of date.

I'm hitting a brick wall within Python 3.9 on this issue. the cache access is at Python3.9 /Library/Frameworks/Python.framework/Versions/3.9/lib/python3.9/types/macholib/dyld.py on line 11 but doesn't do much. What I see is that the pattern 'X.framework/X' is necessary as a file - otherwise nothing works. from ctypes import util from ctypes.macholib.dyld import framework_find # good pa = util.find_library('Python') pb = framework_find('Python') pc = framework_find('Python.framework') # not good. sa = util.find_library('System') sb = framework_find('System') sc = framework_find('System.framework') ga = util.find_library('OpenGL') gb = framework_find('OpenGL') gc = framework_find('OpenGL.framework')