After upgrading to glibc-2.3.3.20040420 a few applications, including firefox 0.8 stopped working, and would exit with no output or error message. a bactrace revealed issues with functions from glibc. Neither recompiling, nor upgrading to firefox 0.9 fixed the problem. After downgrading to 2.3.2-r9 all issues were resolved. I recommend marking glibc-2.3.3.20040420 as ~ppc
Reopen with emerge info