Add signedness warning flag and fix fallout
diff --git a/clients/simple-touch.c b/clients/simple-touch.c
index ade720e..0e2bac6 100644
--- a/clients/simple-touch.c
+++ b/clients/simple-touch.c
@@ -166,7 +166,7 @@
 		0xffff00ff,
 	};
 
-	if (id < ARRAY_LENGTH(colors))
+	if (id < (int32_t) ARRAY_LENGTH(colors))
 		c = colors[id];
 	else
 		c = 0xffffffff;