Apparently Eclipse warns on missing serialVersionUID

Test Plan: ant compile

build.xml

@@ -102,6 +102,7 @@
            >
       <compilerarg value="-Xlint:rawtypes" />
       <compilerarg value="-Xlint:unchecked" />
+      <compilerarg value="-Xlint:serial" />
     </javac>
   </target>
 
@@ -114,6 +115,7 @@
            >
       <compilerarg value="-Xlint:rawtypes" />
       <compilerarg value="-Xlint:unchecked" />
+      <compilerarg value="-Xlint:serial" />
     </javac>
   </target>
 
@@ -155,6 +157,7 @@
       <exclude name="com/facebook/buck/junit/**" />
       <compilerarg value="-Xlint:rawtypes" />
       <compilerarg value="-Xlint:unchecked" />
+      <compilerarg value="-Xlint:serial" />
       <!-- Suppress the warning from implicitly compiling files that are not
            annotation processed. Not sure which files are the culprit -->
       <compilerarg value="-implicit:class" />
@@ -220,6 +223,7 @@
       <src path="${javacc.test.dir}" />
       <compilerarg value="-Xlint:rawtypes" />
       <compilerarg value="-Xlint:unchecked" />
+      <compilerarg value="-Xlint:serial" />
     </javac>
   </target>