diff --git a/gtk/gtkalignment.h b/gtk/gtkalignment.h
index d595c4319a..0c34b4ca95 100644
--- a/gtk/gtkalignment.h
+++ b/gtk/gtkalignment.h
@@ -54,10 +54,10 @@ struct _GtkAlignment
 {
   GtkBin bin;
 
-  gfloat xalign;
-  gfloat yalign;
-  gfloat xscale;
-  gfloat yscale;
+  gfloat GSEAL(xalign);
+  gfloat GSEAL(yalign);
+  gfloat GSEAL(xscale);
+  gfloat GSEAL(yscale);
 };
 
 struct _GtkAlignmentClass