Core: Fix interrupting a thread while on the thread (fixes #692)

CHANGES

@@ -73,6 +73,7 @@ Bugfixes:
  - OpenGL: Fix some shaders causing offset graphics
  - Qt: Fix game unpausing after frame advancing and refocusing
  - GB Timer: Fix sub-M-cycle DIV reset timing and edge triggering
+ - Core: Fix interrupting a thread while on the thread (fixes mgba.io/i/692)
 Misc:
  - SDL: Remove scancode key input
  - GBA Video: Clean up unused timers

src/core/thread.c

@@ -401,11 +401,14 @@ void mCoreThreadInterruptFromThread(struct mCoreThread* threadContext) {
 	MutexLock(&threadContext->stateMutex);
 	++threadContext->interruptDepth;
 	if (threadContext->interruptDepth > 1 || !mCoreThreadIsActive(threadContext)) {
+		if (threadContext->state == THREAD_INTERRUPTING) {
+			threadContext->state = THREAD_INTERRUPTED;
+		}
 		MutexUnlock(&threadContext->stateMutex);
 		return;
 	}
 	threadContext->savedState = threadContext->state;
-	threadContext->state = THREAD_INTERRUPTING;
+	threadContext->state = THREAD_INTERRUPTED;
 	ConditionWake(&threadContext->stateCond);
 	MutexUnlock(&threadContext->stateMutex);
 }