clients: Use zalloc

Signed-off-by: Bryce Harrington <bryce@osg.samsung.com>
diff --git a/clients/simple-shm.c b/clients/simple-shm.c
index e6f0bd0..6d8f608 100644
--- a/clients/simple-shm.c
+++ b/clients/simple-shm.c
@@ -35,6 +35,7 @@
 
 #include <wayland-client.h>
 #include "shared/os-compatibility.h"
+#include "shared/zalloc.h"
 #include "xdg-shell-unstable-v5-client-protocol.h"
 #include "fullscreen-shell-unstable-v1-client-protocol.h"
 
@@ -157,7 +158,7 @@
 {
 	struct window *window;
 
-	window = calloc(1, sizeof *window);
+	window = zalloc(sizeof *window);
 	if (!window)
 		return NULL;