DecoderControl: use GLib forward declarations

src/ClientRead.cxx

@@ -22,6 +22,8 @@
 #include "Main.hxx"
 #include "event/Loop.hxx"
 
+#include <glib.h>
+
 #include <assert.h>
 #include <string.h>
 

src/DecoderControl.cxx

@@ -22,6 +22,8 @@
 #include "MusicPipe.hxx"
 #include "Song.hxx"
 
+#include <glib.h>
+
 #include <assert.h>
 
 #undef G_LOG_DOMAIN

src/DecoderControl.hxx

@@ -26,8 +26,6 @@
 #include "thread/Cond.hxx"
 #include "util/Error.hxx"
 
-#include <glib.h>
-
 #include <assert.h>
 #include <stdint.h>
 
@@ -39,6 +37,7 @@
 struct Song;
 class MusicBuffer;
 class MusicPipe;
+typedef struct _GThread GThread;
 
 enum class DecoderState : uint8_t {
 	STOP = 0,

src/Main.hxx

@@ -20,10 +20,9 @@
 #ifndef MPD_MAIN_HXX
 #define MPD_MAIN_HXX
 
-#include <glib.h>
-
 class EventLoop;
 struct Instance;
+typedef struct _GThread GThread;
 
 extern GThread *main_task;
 

src/OutputControl.cxx

@@ -29,6 +29,8 @@
 #include "FilterPlugin.hxx"
 #include "util/Error.hxx"
 
+#include <glib.h>
+
 #include <assert.h>
 #include <stdlib.h>
 

src/OutputInternal.hxx

@@ -25,14 +25,14 @@
 #include "thread/Mutex.hxx"
 #include "thread/Cond.hxx"
 
-#include <glib.h>
-
 #include <time.h>
 
 class Error;
 class Filter;
 class MusicPipe;
 struct config_param;
+typedef struct _GThread GThread;
+typedef struct _GTimer GTimer;
 
 enum audio_output_command {
 	AO_COMMAND_NONE = 0,

src/output/HttpdInternal.hxx

@@ -30,6 +30,8 @@
 #include "thread/Mutex.hxx"
 #include "event/ServerSocket.hxx"
 
+#include <glib.h>
+
 #include <forward_list>
 
 struct config_param;

src/output/PipeOutputPlugin.cxx

@@ -24,6 +24,8 @@
 #include "util/Error.hxx"
 #include "util/Domain.hxx"
 
+#include <glib.h>
+
 #include <stdio.h>
 #include <errno.h>
 

src/output/WinmmOutputPlugin.cxx

@@ -25,6 +25,8 @@
 #include "util/Error.hxx"
 #include "util/Domain.hxx"
 
+#include <glib.h>
+
 #include <stdlib.h>
 #include <string.h>