fix repeat pattern hanging audio/VGM export

src/engine/engine.cpp

@@ -400,6 +400,7 @@ bool DivEngine::saveAudio(const char* path, int loops, DivAudioExportModes mode)
   exportMode=mode;
   exporting=true;
   stop();
+  repeatPattern=false;
   setOrder(0);
   remainingLoops=loops;
   exportThread=new std::thread(_runExportThread,this);

src/engine/vgmOps.cpp

@@ -385,6 +385,7 @@ void DivEngine::performVGMWrite(SafeWriter* w, DivSystem sys, DivRegWrite& write
 
 SafeWriter* DivEngine::saveVGM(bool* sysToExport, bool loop) {
   stop();
+  repeatPattern=false;
   setOrder(0);
   isBusy.lock();
   double origRate=got.rate;