'Given a list of sources files and the corresponding object files,
returns a list of the pch files that should be depended upon. The
additional wrapping in the return value is for interface compatibility
with make.py on Mac, and xcode_emulation.py.'

def GetObjDependencies(self, sources, objs, arch):

    assert (arch is None)
    if (not self._PchHeader()):
        return []
    pch_ext = os.path.splitext(self.pch_source)[1]
    for source in sources:
        if _LanguageMatchesForPch(os.path.splitext(source)[1], pch_ext):
            return [(None, None, self.output_obj)]
    return []
