The runtime of what, gcc or fixincludes? Whatever solution we come up with, I'd like to avoid duplicating setting STDC_0_IN_SYSTEM_HEADERS, i.e. bad idea to do it once in gcc and once in fixincludes. Better is if we can include the target config file somehow.
Let's not go down the road of including the target config file in more places which are not part of the compiler proper - which are not even inside the gcc directory! I'd like to see this used as an occasion to determine whether we still need this particular hack, which I have never been fond of. If we really still do, the Right Thing would be to add another undocumented built-in preprocessor macro, __STDC_0_IN_SYSTEM_HEADERS__ say, which is defined only if CPP_OPTION(pfile, stdc_0_in_system_headers) is true. zw
