3DS: Ensure core 2 can be used for threaded renderer (fixes #1371)

CHANGES

@@ -26,6 +26,7 @@ Other fixes:
  - Qt: Fix saved scale not getting set on resize (fixes mgba.io/i/1074)
  - CMake: Fix .deb imagemagick dependencies
  - Qt: Fix crash in sprite viewer magnification (fixes mgba.io/i/1362)
+ - 3DS: Ensure core 2 can be used for threaded renderer (fixes mgba.io/i/1371)
 Misc:
  - GBA Savedata: EEPROM performance fixes
  - GBA Savedata: Automatically map 1Mbit Flash files as 1Mbit Flash

src/platform/3ds/main.c

@@ -104,6 +104,7 @@ static C3D_RenderTarget* upscaleBuffer;
 static C3D_Tex upscaleBufferTex;
 
 static aptHookCookie cookie;
+static bool core2;
 
 extern bool allocateRomBuffer(void);
 
@@ -258,9 +259,7 @@ static void _resetCamera(struct m3DSImageSource* imageSource) {
 }
 
 static void _setup(struct mGUIRunner* runner) {
-	bool n3ds = false;
-	APT_CheckNew3DS(&n3ds);
-	if (n3ds) {
+	if (core2) {
 		mCoreConfigSetDefaultIntValue(&runner->config, "threadedVideo", 1);
 		mCoreLoadForeignConfig(runner->core, &runner->config);
 	}
@@ -752,6 +751,10 @@ static void _postAudioBuffer(struct mAVStream* stream, blip_t* left, blip_t* rig
 	}
 }
 
+THREAD_ENTRY _core2Test(void* context) {
+	UNUSED(context);
+}
+
 int main() {
 	rotation.d.sample = _sampleRotation;
 	rotation.d.readTiltX = _readTiltX;
@@ -952,6 +955,12 @@ int main() {
 	APT_SetAppCpuTimeLimit(20);
 	runner.autosave.thread = threadCreate(mGUIAutosaveThread, &runner.autosave, 0x4000, 0x1F, 1, true);
 
+	Thread thread2;
+	if (ThreadCreate(&thread2, _core2Test, NULL) == 0) {
+		core2 = true;
+		ThreadJoin(thread2);
+	}
+
 	mGUIInit(&runner, "3ds");
 
 	_map3DSKey(&runner.params.keyMap, KEY_X, GUI_INPUT_CANCEL);