Log: new logging library API

Prepare to migrate away from GLib.  Currently, we're still using GLib
as a backend.

src/encoder/OpusEncoderPlugin.cxx

@@ -33,9 +33,6 @@
 
 #include <assert.h>
 
-#undef G_LOG_DOMAIN
-#define G_LOG_DOMAIN "opus_encoder"
-
 struct opus_encoder {
 	/** the base class */
 	Encoder encoder;

src/encoder/TwolameEncoderPlugin.cxx

@@ -24,6 +24,7 @@
 #include "ConfigError.hxx"
 #include "util/Error.hxx"
 #include "util/Domain.hxx"
+#include "Log.hxx"
 
 #include <twolame.h>
 
@@ -109,7 +110,8 @@ TwolameEncoder::Configure(const config_param &param, Error &error)
 static Encoder *
 twolame_encoder_init(const config_param &param, Error &error_r)
 {
-	g_debug("libtwolame version %s", get_twolame_version());
+	FormatDebug(twolame_encoder_domain,
+		    "libtwolame version %s", get_twolame_version());
 
 	TwolameEncoder *encoder = new TwolameEncoder();
 

src/encoder/VorbisEncoderPlugin.cxx

@@ -33,9 +33,6 @@
 
 #include <assert.h>
 
-#undef G_LOG_DOMAIN
-#define G_LOG_DOMAIN "vorbis_encoder"
-
 struct vorbis_encoder {
 	/** the base class */
 	Encoder encoder;