apps/nshlib: Don't try to flush output streams if stdio buffered I/O is not supported.
diff --git a/nshlib/nsh_system.c b/nshlib/nsh_system.c
index 62385b1..d78438f 100644
--- a/nshlib/nsh_system.c
+++ b/nshlib/nsh_system.c
@@ -84,7 +84,9 @@
       /* Parse process the command */
 
       (void)nsh_parse(vtbl, argv[1]);
+#if CONFIG_NFILE_STREAMS > 0
       fflush(pstate->cn_outstream);
+#endif
 
       /* Exit upon return */