code: private static String normalizePattern(String p) {
          String pattern = p.replace('/', File.separatorChar)
              .replace('\\', File.separatorChar);
          if (pattern.endsWith(File.separator)) {
              pattern += "**";
          }
          return pattern;
      }
docs: All '/' and '\' characters are replaced by
  <code>File.separatorChar</code>, so the separator used need not
  match <code>File.separatorChar</code>.
  
  <p> When a pattern ends with a '/' or '\', "**" is appended.
  
  @since Ant 1.6.3