'Gets the cflags to include the prefix header for language |lang|.'

def GetInclude(self, lang, arch=None):

    if (self.compile_headers and (lang in self.compiled_headers)):
        return ('-include    %s' % self._CompiledHeader(lang, arch))
    elif self.header:
        return ('-include    %s' % self.header)
    else:
        return ''
