SIGN_EXTEND_CHAR 687 marshal.c          int c = SIGN_EXTEND_CHAR(r_byte(arg));
SIGN_EXTEND_CHAR 2269 parse.y        #define is_identchar(c) (SIGN_EXTEND_CHAR(c)!=-1&&(ISALNUM(c) || (c) == '_' || ismbchar(c)))
SIGN_EXTEND_CHAR 399 regex.c            (destination) += SIGN_EXTEND_CHAR(*(char*)((source) + 1)) << 8; } while (0)