[Python-Dev] what environment variable should contain compiler warning suppression flags?

[Brett Cannon]

I finally realized why clang has not been silencing its warnings about
unused return values: I have -Wno-unused-value set in CFLAGS which
comes before OPT (which defines -Wall) as set in PY_CFLAGS in
Makefile.pre.in.

I could obviously set OPT in my environment, but that would override
the default OPT settings Python uses. I could put it in EXTRA_CFLAGS,
but the README says that's for stuff that tweak binary compatibility.

So basically what I am asking is what environment variable should I
use? If CFLAGS is correct then does anyone have any issues if I change
the order of things for PY_CFLAGS in the Makefile so that CFLAGS comes
after OPT?