[cfe-dev] [RFC] Bump up clang's __GNUC_MINOR__

[Rafael Espíndola]

> With that info in mind I propose changing clang's gcc version to 4.6.3 (currently the latest in the 4.6 series) and keep on bumping it as we gain source-level compatibility with newer GCC versions. If you have any concerns about code that may break if we do that, please share so we can avoid problems.

Some time ago I considered changing clang to impersonate the version
of gcc whose libraries we were using. The problem I was trying to
solve was fixed by patching glibc, but, as you note, there are others
left. I now agree that if we are not going to impersonate gcc 4.2.1,
we should impersonate a newer fixed version.

Pretending to be an old gcc protects us from some of the more obscure
gcc features used in glibc. test/CodeGen/pr9614.c has some cases that
we already have to handle.

I am OK with changing which gcc we impersonate, but we have to try
building quiet a lot of software with different glibc headers to see
if more special cases in would be needed.

ccing chandler since he convinced me to patch glibc last time :-)

> - Ben

Cheers,
Rafael