https://gcc.gnu.org/bugzilla/show_bug.cgi?id=103687
--- Comment #6 from Jakub Jelinek <jakub at gcc dot gnu.org> --- Note, using %I without %p (or %P) in formats certainly looks like a bug, then one can't figure out if it is am or pm time, 08:31:26 is just ambiguous. And my patch changed also the parsing of 12 with %I, previously it would give 12 while not it gives 0 (the new way matches glibc). With %p in addition to it is of course irrelevant, but we could revert to parsing 12 %I as 12 and when %p is specified and it is am turn it into 0.
