10333 cw: error: comparison between pointer and zero character constant

*** 596,606 ****
  static boolean_t
  is_source_file(const char *path)
  {
          char *ext = strrchr(path, '.');
  
!         if ((ext == NULL) || ((ext + 1) == '\0'))
                  return (B_FALSE);
  
          ext += 1;
  
          if ((strcasecmp(ext, "c") == 0) ||
--- 596,606 ----
  static boolean_t
  is_source_file(const char *path)
  {
          char *ext = strrchr(path, '.');
  
!         if ((ext == NULL) || (*(ext + 1) == '\0'))
                  return (B_FALSE);
  
          ext += 1;
  
          if ((strcasecmp(ext, "c") == 0) ||