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)

4 files changed, 6 insertions, 9 deletions

diff --git a/platform/linuxbsd/display_server_x11.cpp b/platform/linuxbsd/display_server_x11.cpp
index 00b90923de..c8632f19f9 100644
--- a/platform/linuxbsd/display_server_x11.cpp
+++ b/platform/linuxbsd/display_server_x11.cpp
@@ -4266,7 +4266,7 @@ DisplayServerX11::DisplayServerX11(const String &p_rendering_driver, WindowMode
 		}
 	}
 
-	events_thread = Thread::create(_poll_events_thread, this);
+	events_thread.start(_poll_events_thread, this);
 
 	_update_real_mouse_position(windows[MAIN_WINDOW_ID]);
 
@@ -4280,9 +4280,7 @@ DisplayServerX11::~DisplayServerX11() {
 	_clipboard_transfer_ownership(XInternAtom(x11_display, "CLIPBOARD", 0), x11_main_window);
 
 	events_thread_done = true;
-	Thread::wait_to_finish(events_thread);
-	memdelete(events_thread);
-	events_thread = nullptr;
+	events_thread.wait_to_finish();
 
 	//destroy all windows
 	for (Map<WindowID, WindowData>::Element *E = windows.front(); E; E = E->next()) {
diff --git a/platform/linuxbsd/display_server_x11.h b/platform/linuxbsd/display_server_x11.h
index 7784ba82b5..906710f933 100644
--- a/platform/linuxbsd/display_server_x11.h
+++ b/platform/linuxbsd/display_server_x11.h
@@ -252,7 +252,7 @@ class DisplayServerX11 : public DisplayServer {
 	void _dispatch_input_event(const Ref<InputEvent> &p_event);
 
 	mutable Mutex events_mutex;
-	Thread *events_thread = nullptr;
+	Thread events_thread;
 	bool events_thread_done = false;
 	LocalVector<XEvent> polled_events;
 	static void _poll_events_thread(void *ud);
diff --git a/platform/linuxbsd/joypad_linux.cpp b/platform/linuxbsd/joypad_linux.cpp
index 291ca49585..42e8e575df 100644
--- a/platform/linuxbsd/joypad_linux.cpp
+++ b/platform/linuxbsd/joypad_linux.cpp
@@ -73,13 +73,12 @@ void JoypadLinux::Joypad::reset() {
 JoypadLinux::JoypadLinux(Input *in) {
 	exit_udev = false;
 	input = in;
-	joy_thread = Thread::create(joy_thread_func, this);
+	joy_thread.start(joy_thread_func, this);
 }
 
 JoypadLinux::~JoypadLinux() {
 	exit_udev = true;
-	Thread::wait_to_finish(joy_thread);
-	memdelete(joy_thread);
+	joy_thread.wait_to_finish();
 	close_joypad();
 }
 
diff --git a/platform/linuxbsd/joypad_linux.h b/platform/linuxbsd/joypad_linux.h
index 20d30b510c..bf343b7ceb 100644
--- a/platform/linuxbsd/joypad_linux.h
+++ b/platform/linuxbsd/joypad_linux.h
@@ -72,7 +72,7 @@ private:
 
 	bool exit_udev;
 	Mutex joy_mutex;
-	Thread *joy_thread;
+	Thread joy_thread;
 	Input *input;
 	Joypad joypads[JOYPADS_MAX];
 	Vector<String> attached_devices;