See attached build log.
(Please do not complain about the need for looking at the build log until you can provide an easy way to open bugs with the correct data picked out of a tinderbox log. Thanks.)
Created attachment 247512 [details]
+ 01 Jul 2012; Justin Lecher <email@example.com> charm-6.2.0.ebuild,
+ Build with gcc-4.7, #424379; repact LDFLAGS, #337558