'Get the modified cflags and implicit dependencies that should be used
for the pch compilation step.'

def GetFlagsModifications(self, input, output, implicit, command, cflags_c, cflags_cc, expand_special):

    if (input == self.pch_source):
        pch_output = [('/Yc' + self._PchHeader())]
        if (command == 'cxx'):
            return ([('cflags_cc', map(expand_special, (cflags_cc + pch_output)))], self.output_obj, [])
        elif (command == 'cc'):
            return ([('cflags_c', map(expand_special, (cflags_c + pch_output)))], self.output_obj, [])
    return ([], output, implicit)
