Update emscripten to 1.39.16

And add a fix for emscripten-core/emscripten#10746.

.github/workflows/emscripten.yml

@@ -2,7 +2,7 @@ name: Emscripten Build
 on: [push]
 
 env:
-  emscripten-version: 1.39.8
+  emscripten-version: 1.39.16
 
 jobs:
   build:

src/sdlmain.cpp

@@ -18,6 +18,12 @@ int main(int argc, char *argv[])
 {
 	SDL_Init(SDL_INIT_VIDEO);
 
+#ifdef __EMSCRIPTEN__
+	// Stop SDL from calling emscripten_sleep() in functions that are called
+	// indirectly, which does not work with ASYNCIFY_IGNORE_INDIRECT=1. For
+	// details, see https://github.com/emscripten-core/emscripten/issues/10746.
+	SDL_SetHint(SDL_HINT_EMSCRIPTEN_ASYNCIFY, "0");
+#endif
 #ifdef __ANDROID__
 	SDL_SetHint(SDL_HINT_ORIENTATIONS, "LandscapeLeft LandscapeRight");
 	Uint32 flags = SDL_WINDOW_FULLSCREEN;