[Bug c/119011] -Wsign-compare: Split it into several levels

[alx at kernel dot org via Gcc-bugs]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=119011

--- Comment #1 from Alejandro Colomar <alx at kernel dot org> ---
Or maybe we can just make -Wsign-compare not warn on that, without adding
levels at all.