Allow mouse plugin to fail gracefully

src/lsi/mouse.c

@@ -52,15 +52,19 @@ int mouse_x, mouse_y, mouse_z;
 
 int mouse_init(void)
 {
+	mouse_x = 0;
+	mouse_y = 0;
+	mouse_z = 0;
+
 	mouse_fd = open(MOUSEDEVICE, O_RDONLY);
-	if (mouse_fd < 0)
-		err(1, "can't open mouse device");
+	if (mouse_fd < 0) {
+		warn("can't open mouse device");
+		mouse_initialised = 0;
+		return 0;
+	}
 
 	vm_register_signal_fd(mouse_fd, VM_MOUSEQ);
 	mouse_initialised = 1;
-	mouse_x = 0;
-	mouse_y = 0;
-	mouse_z = 0;
 
 	return 1;
 }