__all__ = ['CALLY',
           'GAIL',
           'Gecko',
           'J2SE-access-bridge',
           'Qt',
           'VCL.py',
           'WebKitGtk']

__all__ = ['CALLY',
           'gtk',
           'GAIL',
           'Gecko',
           'J2SE-access-bridge',
           'Qt',
           'VCL.py',
           'WebKitGtk']

Add 'gtk' to the toolkit scripts' __init__.py