https://gcc.gnu.org/bugzilla/show_bug.cgi?id=119154
--- Comment #7 from Sam James <sjames at gcc dot gnu.org> --- (In reply to Igor Machado Coelho from comment #6) > I just discovered, and came here to complement this issue, that I found a > very similar situation with -U_FORTIFY_SOURCE. > Just to state it explicitly in case: Ubuntu patches their GCC to default to -D_FORTIFY_SOURCE=3, but that's only done with >= -O1 as optimisation is required for that to be effective (and e.g. glibc headers gate some bits on __OPTIMIZE__ as well accordingly). I imagine that if you consistently pass -U_FORTIFY_SOURCE (to override the default), you should be okay as a workaround for now.
