[Bug c/64862] printf attribute should accept other string types

[tromey at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=64862

--- Comment #9 from Tom Tromey <tromey at gcc dot gnu.org> ---
Created attachment 45413
  --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=45413&action=edit
ancient patch