diff --git a/gcc/config/m68k/a-ux.h b/gcc/config/m68k/a-ux.h
index 0dbcd5b6a8f..74aaa4ea9ad 100644
--- a/gcc/config/m68k/a-ux.h
+++ b/gcc/config/m68k/a-ux.h
@@ -18,7 +18,9 @@ along with GNU CC; see the file COPYING.  If not, write to
 the Free Software Foundation, 59 Temple Place - Suite 330,
 Boston, MA 02111-1307, USA.  */
 
-/*===================================================================*/
+/* This file was renamed from aux.h because of MSDOS: aux.anything
+   isn't usable.  Sigh.  */
+
 /* Execution environment */
 
 #undef TARGET_DEFAULT