https://gcc.gnu.org/bugzilla/show_bug.cgi?id=117342
--- Comment #8 from David Binderman <dcb314 at hotmail dot com> --- gcc $ grep BASE auto-host.h #define HAVE_DECL_BASENAME 1 /* #undef HAVE_GAS_BASE64 */ /* #undef HAVE_LD_PE_DISABLE_DYNAMICBASE */ gcc $ So either I get a different gas when I compile gcc with clang, or something in gcc is assuming base64 works when it doesn't.