diff --git a/src/mesa/main/mtypes.h b/src/mesa/main/mtypes.h
index 74392f8f1f9..592cb48ca3c 100644
--- a/src/mesa/main/mtypes.h
+++ b/src/mesa/main/mtypes.h
@@ -3843,6 +3843,15 @@ struct gl_constants
     */
    GLboolean DisableVaryingPacking;
 
+   /**
+    * UBOs and SSBOs can be packed tightly by the OpenGL implementation when
+    * layout is set as shared (the default) or packed. However most Mesa drivers
+    * just use STD140 for these layouts. This flag allows drivers to use STD430
+    * for packed and shared layouts which allows arrays to be packed more
+    * tightly.
+    */
+   bool UseSTD430AsDefaultPacking;
+
    /**
     * Should meaningful names be generated for compiler temporary variables?
     *