[emscripten] Fixes for data addresses above 2gb

This includes both wasm64 and wasm32 when addressing more than 2gb of
memory.

Fixes: #9052
(cherry picked from commit 3deb07e)

Author: sbc100

include/SDL_stdinc.h

@@ -257,7 +257,7 @@ typedef uint64_t Uint64;
 #define SDL_PRIs64 "I64d"
 #elif defined(PRIs64)
 #define SDL_PRIs64 PRIs64
-#elif defined(__LP64__) && !defined(__APPLE__)
+#elif defined(__LP64__) && !defined(__APPLE__) && !defined(__EMSCRIPTEN__)
 #define SDL_PRIs64 "ld"
 #else
 #define SDL_PRIs64 "lld"

src/audio/emscripten/SDL_emscriptenaudio.c

@@ -39,6 +39,12 @@ static void FeedAudioDevice(_THIS, const void *buf, const int buflen)
     /* *INDENT-OFF* */ /* clang-format off */
     MAIN_THREAD_EM_ASM({
         var SDL2 = Module['SDL2'];
+        /* Convert incoming buf pointer to a HEAPF32 offset. */
+#ifdef __wasm64__
+        var buf = $0 / 4;
+#else
+        var buf = $0 >>> 2;
+#endif
         var numChannels = SDL2.audio.currentOutputBuffer['numberOfChannels'];
         for (var c = 0; c < numChannels; ++c) {
             var channelData = SDL2.audio.currentOutputBuffer['getChannelData'](c);
@@ -47,7 +53,7 @@ static void FeedAudioDevice(_THIS, const void *buf, const int buflen)
             }
 
             for (var j = 0; j < $1; ++j) {
-                channelData[j] = HEAPF32[$0 + ((j*numChannels + c) << 2) >> 2];  /* !!! FIXME: why are these shifts here? */
+                channelData[j] = HEAPF32[buf + (j*numChannels + c)];
             }
         }
     }, buf, buflen / framelen);

src/video/emscripten/SDL_emscriptenframebuffer.c

@@ -89,7 +89,7 @@ int Emscripten_UpdateWindowFramebuffer(_THIS, SDL_Window *window, const SDL_Rect
             SDL2.imageCtx = SDL2.ctx;
         }
         var data = SDL2.image.data;
-        var src = pixels >> 2;
+        var src = pixels / 4;
         var dst = 0;
         var num;
         if (typeof CanvasPixelArray !== 'undefined' && data instanceof CanvasPixelArray) {

src/video/emscripten/SDL_emscriptenmouse.c

@@ -98,7 +98,7 @@ static SDL_Cursor *Emscripten_CreateCursor(SDL_Surface *surface, int hot_x, int
 
         var image = ctx.createImageData(w, h);
         var data = image.data;
-        var src = pixels >> 2;
+        var src = pixels / 4;
         var dst = 0;
         var num;
         if (typeof CanvasPixelArray !== 'undefined' && data instanceof CanvasPixelArray) {