(target_environment): Don't use shell_var if its `value' field is NULL.

diff --git a/variable.c b/variable.c
index 25491c4..3dc8a22 100644 (file)
--- a/variable.c
+++ b/variable.c
@@ -918,15 +918,18 @@ target_environment (struct file *file)
                break;
 
              case v_noexport:
-                /* If this is the SHELL variable and it's not exported, then
-                   add the value from our original environment.  */
-                if (streq (v->name, "SHELL"))
-                  {
-                    extern struct variable shell_var;
-                    v = &shell_var;
-                    break;
-                  }
-                continue;
+               {
+                 /* If this is the SHELL variable and it's not exported,
+                    then add the value from our original environment, if
+                    the original environment defined a value for SHELL.  */
+                 extern struct variable shell_var;
+                 if (streq (v->name, "SHELL") && shell_var.value)
+                   {
+                     v = &shell_var;
+                     break;
+                   }
+                 continue;
+               }
 
              case v_ifset:
                if (v->origin == o_default)