[Bug web/117401] Spell that ./configure --enable-link-mutex is deprecated

[jakub at gcc dot gnu.org via Gcc-bugs]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=117401

--- Comment #3 from Jakub Jelinek <jakub at gcc dot gnu.org> ---
That doesn't really matter.  Anybody who used the option in GCC 13/14 got that
deprecation message.