diff -Nrup a/job.c b/job.c
--- a/job.c	2016-05-21 16:22:32.000000000 -0400
+++ b/job.c	2017-06-11 09:37:31.964954015 -0400
@@ -2561,7 +2561,11 @@ construct_command_argv_internal (char *l
 
   /* See if it is safe to parse commands internally.  */
   if (shell == 0)
-    shell = default_shell;
+    {
+      shell = default_shell;
+      if (shellflags == 0)
+	shellflags = "-c";
+    }
 #ifdef WINDOWS32
   else if (strcmp (shell, default_shell))
   {