output/Init: add constructor overload which calls Configure()

src/output/Init.cxx

@@ -58,6 +58,15 @@ AudioOutput::AudioOutput(const AudioOutputPlugin &_plugin)
 	assert(plugin.play != nullptr);
 }
 
+AudioOutput::AudioOutput(const AudioOutputPlugin &_plugin,
+			 const ConfigBlock &block)
+	:AudioOutput(_plugin)
+{
+	Error error;
+	if (!Configure(block, error))
+		throw std::runtime_error(error.GetMessage());
+}
+
 static const AudioOutputPlugin *
 audio_output_detect(Error &error)
 {

src/output/Internal.hxx

@@ -283,6 +283,13 @@ struct AudioOutput {
 	bool current_chunk_finished;
 
 	AudioOutput(const AudioOutputPlugin &_plugin);
+
+	/**
+	 * Throws #std::runtime_error on error.
+	 */
+	AudioOutput(const AudioOutputPlugin &_plugin,
+		    const ConfigBlock &block);
+
 	~AudioOutput();
 
 	bool Configure(const ConfigBlock &block, Error &error);