https://gcc.gnu.org/bugzilla/show_bug.cgi?id=102664
--- Comment #15 from Jonathan Wakely <redi at gcc dot gnu.org> --- (In reply to Jonathan Wakely from comment #7) > https://www.gnu.org/software/autoconf/manual/autoconf-2.69/html_node/ > Limitations-of-Usual-Tools.html#index-g_t_0040command_007bexpr_007d-1813 > > The expr match regex should not start with ^ (that is implied anyway, and > some versions of expr don't like it) As it says at that link: "Don't use length, substr, match and index." I'll fix it now.
