https://gcc.gnu.org/bugzilla/show_bug.cgi?id=79008
--- Comment #4 from Eric Gallager <egallager at gcc dot gnu.org> --- (In reply to Martin Sebor from comment #2) > > One example of an incompatibility is the following declaration: > > int __attribute__ ((pure)) abs (int); > > where abs() the built-in is actually declared const. GCC doesn't currently > diagnose this except with my patch for bug 81544 (yet to be reviewed). > That's fixed now.