[Bug bootstrap/95555] [11 regression] bootstrap build failure starting with r11-959

[schwab@linux-m68k.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=95555

--- Comment #2 from Andreas Schwab <schwab@linux-m68k.org> ---
alternative_order[0] is guaranteed to be set, because alternative_reject[i] <=
alternative_reject[which_alternative] for i == which_alternative at least.  We
know that which_alternative < recog_data.n_alternatives, otherwise
alternative_reject[which_alternative] would be undefined.