UI: Correct a race condition when loading bgs.

UI/GameInfoCache.cpp

@@ -303,6 +303,11 @@ bool GameInfo::IsPending() {
 	return pending;
 }
 
+bool GameInfo::IsWorking() {
+	lock_guard guard(lock);
+	return working;
+}
+
 void GameInfo::SetTitle(const std::string &newTitle) {
 	lock_guard guard(lock);
 	title = newTitle;
@@ -360,6 +365,7 @@ public:
 		std::string filename = gamePath_;
 		{
 			lock_guard lock(info_->lock);
+			info_->working = true;
 			info_->fileType = Identify_File(info_->GetFileLoader());
 		}
 
@@ -591,6 +597,7 @@ handleELF:
 
 		lock_guard lock(info_->lock);
 		info_->pending = false;
+		info_->working = false;
 		// ILOG("Completed writing info for %s", info_->GetTitle().c_str());
 	}
 
@@ -755,8 +762,14 @@ again:
 	if (!info) {
 		info = new GameInfo();
 	}
+
 	{
 		lock_guard lock(info->lock);
+		if (info->IsWorking()) {
+			// Uh oh, it's currently in process.  It could mark pending = false with the wrong wantFlags.
+			// Let's wait it out, then queue.
+			WaitUntilDone(info);
+		}
 		info->wantFlags |= wantFlags;
 		info->pending = true;
 	}