Strangely, this works better across platforms.

git-svn-id: https://google-web-toolkit.googlecode.com/svn/trunk@6623 8db76d5a-ed1c-0410-87a9-c151d255dfc7
diff --git a/user/build.xml b/user/build.xml
index ccea4f3..c1e6571 100755
--- a/user/build.xml
+++ b/user/build.xml
@@ -144,8 +144,8 @@
     </gwt.checkstyle>
     <gwt.checkstyle.tests>
       <fileset dir="test">
-        <filename name="com/google/**" />
-        <filename name="test/**" />
+        <include name="com/google/**/*.java" />
+        <include name="test/**" />
       </fileset>
     </gwt.checkstyle.tests>
   </target>