diff --git a/src/las.c b/src/las.c
index efaf305000927a5151cd833690a4ceb4ffff86c0..c8ee69b9375fa8ffd160e6e8f4b0b5e29e9c8a00 100644
--- a/src/las.c
+++ b/src/las.c
@@ -5,7 +5,7 @@
 \*/
 /**/
 #include "global.h"
-RCSID("$Id: las.c,v 1.162 2000/02/09 23:49:16 hubbe Exp $");
+RCSID("$Id: las.c,v 1.163 2000/02/15 02:41:26 hubbe Exp $");
 
 #include "language.h"
 #include "interpret.h"
@@ -1496,6 +1496,7 @@ int is_const(node *n)
   if(!n) return 1;
   return !(n->tree_info & (OPT_SIDE_EFFECT |
 			   OPT_NOT_CONST |
+			   OPT_EXTERNAL_DEPEND |
 			   OPT_ASSIGNMENT |
 			   OPT_CASE |
 			   OPT_CONTINUE |