More detailed logging of hid_init() on unixes to detect why

loading of "libudev.so.1" or "libudev.so.0" failed.

src/hidapi/linux/hid.c

@@ -159,7 +159,7 @@ static int hid_wrapper_udev_init()
 	{
 		// Error, close the shared library handle and finish.
 		hid_wrapper_udev_close();
-		return -1;
+		return -2;
 	}
 
 	// Success.