[HTML5] GDNative support via SIDE_MODULE.

Working with emscripten >= 2.0.10

platform/javascript/js/dynlink.pre.js

@@ -0,0 +1 @@
+Module['dynamicLibraries'] = [Module['thisProgram'] + '.side.wasm'];

platform/javascript/js/engine/engine.js

@@ -58,6 +58,9 @@ const Engine = (function () {
 		initPromise = new Promise(function (resolve, reject) {
 			config['locateFile'] = Utils.createLocateRewrite(loadPath);
 			config['instantiateWasm'] = Utils.createInstantiatePromise(loadPromise);
+			// Emscripten configuration.
+			config['thisProgram'] = me.executableName;
+			config['noExitRuntime'] = true;
 			Godot(config).then(function (module) {
 				module['initFS'](me.persistentPaths).then(function (fs_err) {
 					me.rtenv = module;
@@ -119,9 +122,6 @@ const Engine = (function () {
 				locale = navigator.languages ? navigator.languages[0] : navigator.language;
 				locale = locale.split('.')[0];
 			}
-			// Emscripten configuration.
-			me.rtenv['thisProgram'] = me.executableName;
-			me.rtenv['noExitRuntime'] = true;
 			// Godot configuration.
 			me.rtenv['initConfig']({
 				'resizeCanvasOnStart': me.resizeCanvasOnStart,

platform/javascript/js/engine/utils.js

@@ -8,6 +8,8 @@ const Utils = { // eslint-disable-line no-unused-vars
 				return `${execName}.audio.worklet.js`;
 			} else if (path.endsWith('.js')) {
 				return `${execName}.js`;
+			} else if (path.endsWith('.side.wasm')) {
+				return `${execName}.side.wasm`;
 			} else if (path.endsWith('.wasm')) {
 				return `${execName}.wasm`;
 			}