Fix a bug where ::warning() was called with a va_list argument instead of an actual vararg list. Also cleaned up the format for warnings. (Previously some would start with "warning - warning - Warning:" which was a bit redundant)

bool got() { return true; }
extern(C) int printf(char*, ...);
void main()
{
  bool b = true && got();
  printf("%d\n", b ? 1 : 0);
}