Authors: Andreas Mohr <amohr@codeweavers.com>, Dimitrie O. Paun <dimi@cs.toronto.edu>, Patrik Stridvall <ps@leissner.se>
Various warning fixes.

diff --git a/dlls/comctl32/treeview.c b/dlls/comctl32/treeview.c
index 65c58ea..b04678f 100644
--- a/dlls/comctl32/treeview.c
+++ b/dlls/comctl32/treeview.c
@@ -27,6 +27,8 @@
 #include <assert.h>
 #include <string.h>
 #include <limits.h>
+#include <stdlib.h>
+
 #include "winbase.h"
 #include "wingdi.h"
 #include "wine/winestring.h"