I tried compiling libgif and libunfig with the following CFLAGS, unsuccessfuly: CFLAGS="-mcpu=athlon-tbird -O2" I did manage to get them to compile by unsetting the CFLAGS and CXXFLAGS, however. I think this is probably pretty severe for new system builds since kde and gnome depend on it. I originally had ACCEPT_KEYWORDS="~x86" but removed that and downgraded everything to stable releases, still with no success.
Decided i was an idiot and used a 0 (zero) instead of an O (letter o).