https://gcc.gnu.org/bugzilla/show_bug.cgi?id=67093
--- Comment #5 from Jonathan Wakely <redi at gcc dot gnu.org> --- Surely GCC only warns here because glibc adds the attribute to the execl declaration, so the bug is in glibc. GCC interprets the nonnull attribute to mean the argument *must* be non-null, and even optimises based on that assumption. So the attribute should not be used for recommendations, only requirements.
