Add an Option::optionName() function that returns a string describing the option name, with leading dashes. As a result, OptionsParser::parseValueError() function becomes a single-line function and can be inlined in its caller. Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com> Reviewed-by: Kieran Bingham <kieran.bingham@ideasonboard.com>