Search for all the python related files, and construct the pythonXX.zip
    According to
    # http://randomsplat.com/id5-cross-compiling-python-for-embedded-linux.html
    site-packages, config and lib-dynload will be not included.

def make_python_zip():
    '''
    Search for all the python related files, and construct the pythonXX.zip
    According to
    # http://randomsplat.com/id5-cross-compiling-python-for-embedded-linux.html
    site-packages, config and lib-dynload will be not included.
    '''

    if not exists('private'):
        print('No compiled python is present to zip, skipping.')
        return

    global python_files
    d = realpath(join('private', 'lib', 'python2.7'))

    def select(fn):
        if is_blacklist(fn):
            return False
        fn = realpath(fn)
        assert(fn.startswith(d))
        fn = fn[len(d):]
        if (fn.startswith('/site-packages/')
                or fn.startswith('/config/')
                or fn.startswith('/lib-dynload/')
                or fn.startswith('/libpymodules.so')):
            return False
        return fn

    # get a list of all python file
    python_files = [x for x in listfiles(d) if select(x)]

    # create the final zipfile
    zfn = join('private', 'lib', 'python27.zip')
    zf = ZipFile(zfn, 'w')

    # put all the python files in it
    for fn in python_files:
        afn = fn[len(d):]
        zf.write(fn, afn)
    zf.close()