hid: define easy error data setter function

Sets all error data, including an optional contextual error message
which is supposed to be a non-freeable constant string
such as a string literal.

Contextual error messages are meant to be used in the cases
the libusb documentation goes into detail as to what happened.
Passing NULL will produce a message with just the libusb_error_name
and the libusb_strerror results. Passing a string literal will produce
a message that contains the additional context in addition to the error
name and message.

Author: matheusmoreira

libusb/hid.c

@@ -422,6 +422,11 @@ static wchar_t *libusb_strerror_wchar(int error) {
 	return libusb_error_wchar(error, libusb_strerror);
 }
 
+static void set_error(hid_device *dev, int error, const char *error_context)
+{
+	dev->error = error;
+	dev->error_context = error_context;
+}
 
 /* This function returns a newly allocated wide string containing the USB
    device string numbered by the index. The returned string must be freed