ONIGENC_MBC_CASE_FOLD 3206 regcomp.c          len = ONIGENC_MBC_CASE_FOLD(reg->enc, reg->case_fold_flag, &p, end, buf);
ONIGENC_MBC_CASE_FOLD  996 regexec.c          len1 = ONIGENC_MBC_CASE_FOLD(enc, case_fold_flag, &s1, text_end, buf1);
ONIGENC_MBC_CASE_FOLD  997 regexec.c          len2 = ONIGENC_MBC_CASE_FOLD(enc, case_fold_flag, &s2, text_end, buf2);
ONIGENC_MBC_CASE_FOLD 1453 regexec.c      	len = ONIGENC_MBC_CASE_FOLD(encode,
ONIGENC_MBC_CASE_FOLD 1547 regexec.c      	  len = ONIGENC_MBC_CASE_FOLD(encode,
ONIGENC_MBC_CASE_FOLD 2797 regexec.c          lowlen = ONIGENC_MBC_CASE_FOLD(enc, case_fold_flag, &p, end, lowbuf);