Switch on GWT incremental compilation.

http://gwt-code-reviews.appspot.com/1461802/


git-svn-id: https://google-web-toolkit.googlecode.com/svn/trunk@10379 8db76d5a-ed1c-0410-87a9-c151d255dfc7
diff --git a/dev/core/src/com/google/gwt/dev/jjs/impl/GwtAstBuilder.java b/dev/core/src/com/google/gwt/dev/jjs/impl/GwtAstBuilder.java
index a2c6575..483275f 100644
--- a/dev/core/src/com/google/gwt/dev/jjs/impl/GwtAstBuilder.java
+++ b/dev/core/src/com/google/gwt/dev/jjs/impl/GwtAstBuilder.java
@@ -2758,7 +2758,7 @@
     }
   }
 
-  public static boolean ENABLED = System.getProperties().containsKey("x.gwt.astBuilder");
+  public static boolean ENABLED = !System.getProperties().containsKey("x.gwt.noAstBuilder");
 
   /**
    * Manually tracked version count.