[Web] Small fixes and enhancements.

- "Definitive" fix for ENOENT randomly disappearing from emscripten.
- Proper shutdown when setup fails.
- Re-enable WebGL explicit buffer swap.
- Re-enable optional per-pixel transparency.
- Add type cast to make closure compiler happy.
- Remove emscripten Safari WebGL workaround.
- Improve AudioWorklet cleanup.

platform/web/js/libs/audio.worklet.js

@@ -133,6 +133,8 @@ class GodotProcessor extends AudioWorkletProcessor {
 			this.running = false;
 			this.output = null;
 			this.input = null;
+			this.lock = null;
+			this.notifier = null;
 		} else if (p_cmd === 'start_nothreads') {
 			this.output = new RingBuffer(p_data[0], p_data[0].length, false);
 		} else if (p_cmd === 'chunk') {

platform/web/js/libs/library_godot_audio.js

@@ -339,16 +339,21 @@ const GodotAudioWorklet = {
 				if (GodotAudioWorklet.promise === null) {
 					return;
 				}
-				GodotAudioWorklet.promise.then(function () {
+				const p = GodotAudioWorklet.promise;
+				p.then(function () {
 					GodotAudioWorklet.worklet.port.postMessage({
 						'cmd': 'stop',
 						'data': null,
 					});
 					GodotAudioWorklet.worklet.disconnect();
+					GodotAudioWorklet.worklet.port.onmessage = null;
 					GodotAudioWorklet.worklet = null;
 					GodotAudioWorklet.promise = null;
 					resolve();
-				}).catch(function (err) { /* aborted? */ });
+				}).catch(function (err) {
+					// Aborted?
+					GodotRuntime.error(err);
+				});
 			});
 		},
 	},

platform/web/js/libs/library_godot_os.js

@@ -106,12 +106,14 @@ autoAddDeps(GodotConfig, '$GodotConfig');
 mergeInto(LibraryManager.library, GodotConfig);
 
 const GodotFS = {
-	$GodotFS__deps: ['$ERRNO_CODES', '$FS', '$IDBFS', '$GodotRuntime'],
+	$GodotFS__deps: ['$FS', '$IDBFS', '$GodotRuntime'],
 	$GodotFS__postset: [
 		'Module["initFS"] = GodotFS.init;',
 		'Module["copyToFS"] = GodotFS.copy_to_fs;',
 	].join(''),
 	$GodotFS: {
+		// ERRNO_CODES works every odd version of emscripten, but this will break too eventually.
+		ENOENT: 44,
 		_idbfs: false,
 		_syncing: false,
 		_mount_points: [],
@@ -138,8 +140,9 @@ const GodotFS = {
 				try {
 					FS.stat(dir);
 				} catch (e) {
-					if (e.errno !== ERRNO_CODES.ENOENT) {
-						throw e;
+					if (e.errno !== GodotFS.ENOENT) {
+						// Let mkdirTree throw in case, we cannot trust the above check.
+						GodotRuntime.error(e);
 					}
 					FS.mkdirTree(dir);
 				}
@@ -208,8 +211,9 @@ const GodotFS = {
 			try {
 				FS.stat(dir);
 			} catch (e) {
-				if (e.errno !== ERRNO_CODES.ENOENT) {
-					throw e;
+				if (e.errno !== GodotFS.ENOENT) {
+					// Let mkdirTree throw in case, we cannot trust the above check.
+					GodotRuntime.error(e);
 				}
 				FS.mkdirTree(dir);
 			}