def dlls_in_dir(directory):
    """Returns *.dll, *.so, *.dylib in given directory."""
    files = []
    files.extend(glob.glob(os.path.join(directory, '*.so')))
    files.extend(glob.glob(os.path.join(directory, '*.dll')))
    files.extend(glob.glob(os.path.join(directory, '*.dylib')))
    return files