-fomit-frame-pointer should be enabled by setting CAN_DEBUG_WITHOUT_FP, but only after thorough testing for every multilib that that debugging is not impeded, and that average benchmark scores are indeed improved.
done since http://gcc.gnu.org/ml/gcc-patches/2010-01/msg01147.html needed ACCUMULATE_OUTGOING_ARG to fix unwinding (can go back to previous behavior with -mno-accumulate-outgoing-args -fno-omit-frame-pointer)