diff --git a/lib/getdate.c.cvs b/lib/getdate.c.cvs
index 594ae81a3..48dff2329 100644
--- a/lib/getdate.c.cvs
+++ b/lib/getdate.c.cvs
@@ -47,6 +47,11 @@
 #define YYDEBUG 0
 #endif
 
+#ifndef YYSTACK_USE_ALLOCA
+  /* to satisfy gcc -Wundef, we set this to 0 */
+#define YYSTACK_USE_ALLOCA 0
+#endif
+
 /* Since the code of getdate.y is not included in the Emacs executable
    itself, there is no need to #define static in this file.  Even if
    the code were included in the Emacs executable, it probably
@@ -1758,7 +1763,7 @@ ToHour (Hours, Meridian)
     default:
       abort ();
     }
-  /* NOTREACHED */
+  /* NOTREACHED - but make gcc happy! */
 }
 
 static int