#!/usr/bin/env python

def configuration(parent_package='',top_path=None):
    from numpy.distutils.misc_util import Configuration

    config = Configuration('signal', parent_package, top_path)

    config.add_data_dir('tests')

    config.add_extension('sigtools',
                         sources=['sigtoolsmodule.c',
                                  'firfilter.c','medianfilter.c'],
                         depends = ['sigtools.h']
    )

    config.add_extension('spline',
        sources = ['splinemodule.c','S_bspline_util.c','D_bspline_util.c',
                   'C_bspline_util.c','Z_bspline_util.c','bspline_util.c'],
    )

    return config

if __name__ == '__main__':
    from numpy.distutils.core import setup
    setup(**configuration(top_path='').todict())

#!/usr/bin/env python

def configuration(parent_package='',top_path=None):
    from numpy.distutils.misc_util import Configuration

    config = Configuration('signal', parent_package, top_path)

    config.add_data_dir('tests')

    config.add_extension('sigtools',
                         sources=['sigtoolsmodule.c',
                                  'firfilter.c','medianfilter.c'],
                         depends = ['sigtools.h', 'newsig.c']
    )

    config.add_extension('spline',
        sources = ['splinemodule.c','S_bspline_util.c','D_bspline_util.c',
                   'C_bspline_util.c','Z_bspline_util.c','bspline_util.c'],
    )

    return config

if __name__ == '__main__':
    from numpy.distutils.core import setup
    setup(**configuration(top_path='').todict())

Add newsig.c as a dependency to sigtools module.