[nautilus] file-undo-operations: fix missing include

[Carlos Soriano Sánchez <csoriano src gnome org>]

commit ab68326e67f67f688b94da6c0f8e54ddb941e18c
Author: Carlos Soriano <csoriano gnome org>
Date:   Mon Apr 18 10:14:13 2016 +0200

    file-undo-operations: fix missing include
    
    Having so many deprecation warnings obscure the real warnings... :/
    Should run more frequently with those disabled.

 .../nautilus-file-undo-operations.c                |    1 +
 1 files changed, 1 insertions(+), 0 deletions(-)
---
diff --git a/libnautilus-private/nautilus-file-undo-operations.c 
b/libnautilus-private/nautilus-file-undo-operations.c
index 30a02e9..25d90bb 100644
--- a/libnautilus-private/nautilus-file-undo-operations.c
+++ b/libnautilus-private/nautilus-file-undo-operations.c
@@ -23,6 +23,7 @@
  */
 
 #include <config.h>
+#include <stdlib.h>
 
 #include "nautilus-file-undo-operations.h"