STK_ALT           523 ext/mbstring/oniguruma/regexec.c   stk->type = STK_ALT;\
STK_ALT           561 ext/mbstring/oniguruma/regexec.c #define STACK_PUSH_ALT(pat,s,sprev)     STACK_PUSH(STK_ALT,pat,s,sprev)
STK_ALT          1290 ext/mbstring/oniguruma/regexec.c   STACK_PUSH_ENSURED(STK_ALT, FinishCode);  /* bottom stack */