[libc-commits] [libc] [libc][complex] Silence `pedantic` warning (PR #112239)

[Nick Desaulniers via libc-commits]

nickdesaulniers wrote:

> And for some reason, adding Wno-c99-extensions there still not suppresses _Complex warnings.

Yes it does: https://godbolt.org/z/aacj54rdM `-Wno-*` needs to occur AFTER `-Wpedantic`.  The way these work in Clang (and GCC which Clang matches its behavior from (AFAIK)) is that the last occurrence of these on the command line "wins."  `-Wpedantic` is a "group" that enables a bunch of warnings implicitly, so then after you'd need to re-disable the flags you want.

`-Wpedatic` to me means we're sticking with strict ISO C (or C++).  If we use extensions (that are supported by the two compilers we support), then `-Wpedantic` doesn't add much value IMO.

https://github.com/llvm/llvm-project/pull/112239