http://gcc.gnu.org/bugzilla/show_bug.cgi?id=42734
--- Comment #33 from Jonathan Wakely <redi at gcc dot gnu.org> 2010-10-15 19:45:22 UTC --- hmm, I should check, but I'm not home right now ... the problem could be that that the library only checks SYNC_HAVE_COMPARE_AND_SWAP t configure time, and (I think) pre-defines _GLIBCXX_ATOMIC_BUILTINS in config.h, which causes the library headers to think we have the sync builtins, even if the user later uses -march=i386 which disables them.
