alt_match_null_string_p 3668 regex.cpp      static boolean alt_match_null_string_p(unsigned char *p,
alt_match_null_string_p 5157 regex.cpp                        if (!alt_match_null_string_p (p1, p1 + mcnt - 3,
alt_match_null_string_p 5187 regex.cpp                    if (!alt_match_null_string_p (p1, p1 + mcnt, reg_info))