fix parsing negative number

bint.cc

@@ -30,7 +30,7 @@ zval * bint::parse(const std::string &ben, size_t &pt) {
  ++pt;
  std::string strint = "";
  while (ben[pt] != 'e') strint += ben[pt++];
- long result = std::stoull(strint);
+ long result = std::stoll(strint);
  ++pt;
 
  zval _zv;