[gnome-system-monitor] Add missing <config.h> include.

[Benoît Dejean <bdejean src gnome org>]

commit ecb1ff34bab0fe1a7a8f76dc4f403c55292bc053
Author: Benoît Dejean <bdejean gmail com>
Date:   Sun Feb 19 07:58:58 2017 +0100

    Add missing <config.h> include.

 src/cgroups.cpp |    1 +
 1 files changed, 1 insertions(+), 0 deletions(-)
---
diff --git a/src/cgroups.cpp b/src/cgroups.cpp
index 23d10c1..075e4a8 100644
--- a/src/cgroups.cpp
+++ b/src/cgroups.cpp
@@ -1,4 +1,5 @@
 /* -*- tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
+#include <config.h>
 #include "cgroups.h"
 #include "util.h"