[gnome-todo] utils: Include the correct headers

[Georges Basile Stavracas Neto <gbsneto src gnome org>]

commit 8762aacb839b8e8160ed6eed50d1c96ebe1beacd
Author: Georges Basile Stavracas Neto <georges stavracas gmail com>
Date:   Sun Feb 11 19:54:58 2018 +0000

    utils: Include the correct headers

 src/gtd-utils.c | 2 ++
 1 file changed, 2 insertions(+)
---
diff --git a/src/gtd-utils.c b/src/gtd-utils.c
index 636ad81..dc77bc7 100644
--- a/src/gtd-utils.c
+++ b/src/gtd-utils.c
@@ -20,6 +20,8 @@
 
 #include "gtd-utils.h"
 
+#include <string.h>
+
 gchar*
 gtd_str_replace (const gchar *source,
                  const gchar *search,