When messaging nil, the return values are:

Ints up to 64 bits: 0
Pointers: nil
Structs: undefined
Float, double, long double: 0.0 on i386; 0.0 on ppc 10.5 and later; undefined on ppc 10.4 and earlier

mogenerator 1.16 creates code like this:

• (int)volumeTypeValue {
  NSNumber *result = [self volumeType];
  return result ? [result intValue] : 0;
  }

The check for nil is not needed if the min deployment target is 10.5. Since mogenerator is now also unconditionally using @dynamic, 10.5 is now required, right? If so, we can remove these nil checks.