ONIG_OPTIMIZE_EXACT_IC 4894 regcomp.c          reg->optimize = ONIG_OPTIMIZE_EXACT_IC;
ONIG_OPTIMIZE_EXACT_IC 3159 regexec.c        case ONIG_OPTIMIZE_EXACT_IC:
ONIG_OPTIMIZE_EXACT_IC 3282 regexec.c        case ONIG_OPTIMIZE_EXACT_IC: