Make enabling static rect VB configurable by user config file.

git-svn-id: http://skia.googlecode.com/svn/trunk@753 2bbb7eff-a529-9590-31e7-b0007b416f81
diff --git a/gpu/include/GrConfig.h b/gpu/include/GrConfig.h
index b599a53..4c5ddd6 100644
--- a/gpu/include/GrConfig.h
+++ b/gpu/include/GrConfig.h
@@ -305,6 +305,10 @@
     #define GR_GL_LOG_CALLS 0 
 #endif
 
+#if !defined(GR_STATIC_RECT_VB)
+    #define GR_STATIC_RECT_VB 0
+#endif
+
 ///////////////////////////////////////////////////////////////////////////////
 // tail section:
 //