'Writes rules to match MSVS\'s implicit idl handling.'

def WriteWinIdlFiles(self, spec, prebuild):

    assert (self.flavor == 'win')
    if self.msvs_settings.HasExplicitIdlRulesOrActions(spec):
        return []
    outputs = []
    for source in filter((lambda x: x.endswith('.idl')), spec['sources']):
        self._WinIdlRule(source, prebuild, outputs)
    return outputs
