Added Git Revision to GWT version file

client-compiler/build.xml

@@ -23,7 +23,16 @@
 	</union>
 
 	<target name="jar">
-		<echo file="${result.dir}/com/google/gwt/dev/About.properties">gwt.version=${vaadin.version}</echo>
+		<!-- Get Git revision -->
+		<exec executable="git" outputproperty="git.revision" failifexecutionfails="false" errorproperty="">
+			 <arg value="describe"/>
+			 <arg value="--tags"/>
+			 <arg value="--always"/>
+			 <arg value="HEAD"/>
+		</exec> 
+		 
+		<echo file="${result.dir}/com/google/gwt/dev/About.properties">gwt.version=${vaadin.version}
+gwt.svnrev=${git.revision}</echo>
 
 		<antcall target="common.jar">
 			<reference refid="compiler.includes" torefid="extra.jar.includes" />