https://gcc.gnu.org/bugzilla/show_bug.cgi?id=69744
--- Comment #3 from Jonathan Wakely <redi at gcc dot gnu.org> --- (In reply to Richard Biener from comment #2) > stddef.h is provided by GCC itself and thus likely needs "fixing" for OpenBSD > (see gcc/ginclude/stddef.h) Yeah, for some reason that header isn't used for this target: # 1 "/home/vext01/research/warmup_experiment/work/gcc/sd_build/x86_64-unknown-openbsd5.8/libstdc++-v3/include/cstddef" 1 # 42 "/home/vext01/research/warmup_experiment/work/gcc/sd_build/x86_64-unknown-openbsd5.8/libstdc++-v3/include/cstddef" # 43 "/home/vext01/research/warmup_experiment/work/gcc/sd_build/x86_64-unknown-openbsd5.8/libstdc++-v3/include/cstddef" 3 # 1 "/home/vext01/research/warmup_experiment/work/gcc/sd_build/gcc/include-fixed/stddef.h" 1 3 4 # 54 "/home/vext01/research/warmup_experiment/work/gcc/sd_build/gcc/include-fixed/stddef.h" 3 4 typedef long int ptrdiff_t; # 80 "/home/vext01/research/warmup_experiment/work/gcc/sd_build/gcc/include-fixed/stddef.h" 3 4 typedef __wint_t wint_t; typedef __mbstate_t mbstate_t; # 46 "/home/vext01/research/warmup_experiment/work/gcc/sd_build/x86_64-unknown-openbsd5.8/libstdc++-v3/include/cstddef" 2 3 namespace std { using ::max_align_t; } Does include-fixed/stddef.h take priority over GCC's own stddef.h ?