libdwfl: Another segment lookup table nit.
diff --git a/libdwfl/segment.c b/libdwfl/segment.c
index d39fdab..9d78c87 100644
--- a/libdwfl/segment.c
+++ b/libdwfl/segment.c
@@ -121,6 +121,8 @@
     {
       dwfl->lookup_addr[i] = start;
       dwfl->lookup_segndx[i] = segndx;
+      if (dwfl->lookup_module != NULL)
+	dwfl->lookup_module[i] = NULL;
       ++i;
     }
   else
@@ -130,6 +132,8 @@
     {
       dwfl->lookup_addr[i] = end;
       dwfl->lookup_segndx[i] = -1;
+      if (dwfl->lookup_module != NULL)
+	dwfl->lookup_module[i] = NULL;
     }
 
   dwfl->lookup_elts += need;