> Why do you think teaching this to many pkgs is better than teaching it to 
> the compiler wrapper (similar to what PKGSRC_COMPILER already does see 
> pkgsrc/mk/compiler.mk)?

You surely could do that, but then (of course depending on how you do it)
there is no chance for a package not to make use of it. There might be
reasons to do so (I just learned for example that
pkgtools/pkg_install-info fails to compile with gcc -O3 on a Pentium and
gcc 3.3.5).
There is _WRAP_EXTRA_ARGS.CC in mk/wrapper/bsd.wrapper.mk. I haven't tried
to preset it in /etc/mk.conf, but you might try so (please share your
results).
Irrespective of that I think that packages should try to honor CFLAGS
etc. settings.

-- 
Georg Schwarz    http://home.pages.de/~schwarz/
 georg.schwarz@freenet.de  +49 178 8545053