clients: Use zalloc

Signed-off-by: Bryce Harrington <bryce@osg.samsung.com>
diff --git a/clients/simple-damage.c b/clients/simple-damage.c
index 0353ccc..321b90f 100644
--- a/clients/simple-damage.c
+++ b/clients/simple-damage.c
@@ -37,6 +37,7 @@
 
 #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"
 #include "scaler-client-protocol.h"
@@ -271,7 +272,7 @@
 		exit(1);
 	}
 
-	window = calloc(1, sizeof *window);
+	window = zalloc(sizeof *window);
 	if (!window)
 		return NULL;