[llvm-dev] Bootstrapping clang/LLVM with ELLCC

[Tim Northover via llvm-dev]

> Yeah, that was probably excessively harsh. But people could have
> legitimate reasons for #including <stdio.h> (presumably) but making
> use of "fopen64". You should see the hoops libc++ jumps through to
> avoid such mishaps.

Looks like Musl's own definitions are protected by
"_LARGEFILE64_SOURCE || _GNU_SOURCE". My guess is that we end up
defining _GNU_SOURCE for whatever reason, which would make the #undefs
entirely logical in that regime. (Completely unchecked, of course).

Cheers.

Tim.