def list_fonts(directory, extensions):
    """
    Return a list of all fonts matching any of the extensions,
    possibly upper-cased, found recursively under the directory.
    """
    pattern = ";".join(["*.%s;*.%s" % (ext, ext.upper()) for ext in extensions])
    return cbook.listFiles(directory, pattern)

def OSXInstalledFonts(directories=None, fontext='ttf'):
    """
    Get list of font files on OS X - ignores font suffix by default.
    """
    if directories is None:
        directories = OSXFontDirectories

    fontext = get_fontext_synonyms(fontext)

    files = []
    for path in directories:
        if fontext is None:
            files.extend(cbook.listFiles(path, '*'))
        else:
            files.extend(list_fonts(path, fontext))
    return files