$OpenBSD: patch-drivers_libusb_c,v 1.2 2014/01/07 21:55:54 sthen Exp $
--- drivers/libusb.c.orig	Wed Jul 31 21:41:31 2013
+++ drivers/libusb.c	Thu Nov 21 22:08:48 2013
@@ -375,7 +375,9 @@ static int libusb_strerror(const int ret, const char *
 		return 0;
 
 	case -EOVERFLOW:	/* Value too large for defined data type */
+#ifdef EPROTO
 	case -EPROTO:	/* Protocol error */
+#endif
 		upsdebugx(2, "%s: %s", desc, usb_strerror());
 		return 0;
 
