Main: use ThreadId instead of GThread*

src/Main.cxx

@@ -58,6 +58,7 @@
 #include "system/FatalError.hxx"
 #include "util/Error.hxx"
 #include "util/Domain.hxx"
+#include "thread/Id.hxx"
 #include "ConfigGlobal.hxx"
 #include "ConfigData.hxx"
 #include "ConfigDefaults.hxx"
@@ -99,7 +100,7 @@ enum {
 
 static constexpr Domain main_domain("main");
 
-GThread *main_task;
+ThreadId main_thread;
 EventLoop *main_loop;
 
 Instance *instance;
@@ -389,7 +390,7 @@ int mpd_main(int argc, char *argv[])
 		return EXIT_FAILURE;
 	}
 
-	main_task = g_thread_self();
+	main_thread = ThreadId::GetCurrent();
 	main_loop = new EventLoop(EventLoop::Default());
 
 	instance = new Instance();

src/Main.hxx

@@ -20,11 +20,11 @@
 #ifndef MPD_MAIN_HXX
 #define MPD_MAIN_HXX
 
+class ThreadId;
 class EventLoop;
 struct Instance;
-typedef struct _GThread GThread;
 
-extern GThread *main_task;
+extern ThreadId main_thread;
 
 extern EventLoop *main_loop;
 

src/UpdateGlue.cxx

@@ -33,6 +33,7 @@
 #include "Main.hxx"
 #include "Instance.hxx"
 #include "system/FatalError.hxx"
+#include "thread/Id.hxx"
 
 #include <glib.h>
 
@@ -92,7 +93,7 @@ static void * update_task(void *_path)
 static void
 spawn_update_task(const char *path)
 {
-	assert(g_thread_self() == main_task);
+	assert(main_thread.IsInside());
 
 	progress = UPDATE_PROGRESS_RUNNING;
 	modified = false;
@@ -115,7 +116,7 @@ spawn_update_task(const char *path)
 unsigned
 update_enqueue(const char *path, bool _discard)
 {
-	assert(g_thread_self() == main_task);
+	assert(main_thread.IsInside());
 
 	if (!db_is_simple() || !mapper_has_music_directory())
 		return 0;