Modernize Thread

- Based on C++11's `thread` and `thread_local`
- No more need to allocate-deallocate or check for null
- No pointer anymore, just a member variable
- Platform-specific implementations no longer needed (except for the few cases of non-portable functions)
- Simpler for `NO_THREADS`
- Thread ids are now the same across platforms (main is 1; others follow)

drivers/pulseaudio/audio_driver_pulseaudio.cpp

@@ -294,7 +294,7 @@ Error AudioDriverPulseAudio::init() {
 
 	Error err = init_device();
 	if (err == OK) {
-		thread = Thread::create(AudioDriverPulseAudio::thread_func, this);
+		thread.start(AudioDriverPulseAudio::thread_func, this);
 	}
 
 	return OK;
@@ -599,15 +599,11 @@ void AudioDriverPulseAudio::set_device(String device) {
 
 void AudioDriverPulseAudio::lock() {
 
-	if (!thread)
-		return;
 	mutex.lock();
 }
 
 void AudioDriverPulseAudio::unlock() {
 
-	if (!thread)
-		return;
 	mutex.unlock();
 }
 
@@ -622,11 +618,11 @@ void AudioDriverPulseAudio::finish_device() {
 
 void AudioDriverPulseAudio::finish() {
 
-	if (!thread)
+	if (!thread.is_started())
 		return;
 
 	exit_thread = true;
-	Thread::wait_to_finish(thread);
+	thread.wait_to_finish();
 
 	finish_device();
 
@@ -640,10 +636,6 @@ void AudioDriverPulseAudio::finish() {
 		pa_mainloop_free(pa_ml);
 		pa_ml = NULL;
 	}
-
-	memdelete(thread);
-
-	thread = NULL;
 }
 
 Error AudioDriverPulseAudio::capture_init_device() {
@@ -797,7 +789,6 @@ String AudioDriverPulseAudio::capture_get_device() {
 }
 
 AudioDriverPulseAudio::AudioDriverPulseAudio() :
-		thread(NULL),
 		pa_ml(NULL),
 		pa_ctx(NULL),
 		pa_str(NULL),

drivers/pulseaudio/audio_driver_pulseaudio.h

@@ -41,7 +41,7 @@
 
 class AudioDriverPulseAudio : public AudioDriver {
 
-	Thread *thread;
+	Thread thread;
 	Mutex mutex;
 
 	pa_mainloop *pa_ml;