diff -Naur sed-4.1.4.orig/lib/regex_internal.c sed-4.1.4/lib/regex_internal.c
--- sed-4.1.4.orig/lib/regex_internal.c	2005-01-28 09:07:56 +0000
+++ sed-4.1.4/lib/regex_internal.c	2005-08-24 03:20:28 +0000
@@ -885,8 +885,9 @@
 {
   set->alloc = size;
   set->nelem = 0;
-  set->elems = re_malloc (int, size);
-  if (BE (set->elems == NULL, 0))
+  set->elems = re_malloc (int, size); /* can be NULL if size == 0
+				(see re_node_set_init_empty(set)) */
+  if (BE (set->elems == NULL && size != 0, 0))
     return REG_ESPACE;
   return REG_NOERROR;
 }