https://gcc.gnu.org/bugzilla/show_bug.cgi?id=117028
--- Comment #5 from Joseph S. Myers <jsm28 at gcc dot gnu.org> --- Obsolescence is generally unhelpful when there is no non-obsolescent alternative in previous standard versions, given that much code needs to work with a range of implementation and standard versions; octal literals are extremely widely used and the new syntax doesn't exist before C23.
