Update qtsingleapplication

To upstream version a8dda66d7738cde9042b87db27993f710ae3eeeb

src/app/qtsingleapplication/qtlocalpeer.cpp

@@ -176,8 +176,17 @@ void QtLocalPeer::receiveConnection()
     if (!socket)
         return;
 
-    while (socket->bytesAvailable() < (int)sizeof(quint32))
+    while (true) {
+        if (socket->state() == QLocalSocket::UnconnectedState) {
+            qWarning("QtLocalPeer: Peer disconnected");
+            delete socket;
+            return;
+        }
+        if (socket->bytesAvailable() >= qint64(sizeof(quint32)))
+            break;
         socket->waitForReadyRead();
+    }
+
     QDataStream ds(socket);
     QByteArray uMsg;
     quint32 remaining;