TQObject::activate_signal: uniformly apply if(sol) checks

It seems the situation where sol is NULL is theoretically possible. So
keep the checks and apply those uniformly to all instances of access to
`sol`.

Signed-off-by: Alexander Golubev <fatzer2@gmail.com>

src/kernel/qobject.cpp

@@ -2809,10 +2809,10 @@ void TQObject::activate_signal( TQConnectionList *clist, TQUObject *o )
 	TQObject *object = c->object();
 	TQObject *oldSender;
 	TQSenderObjectList* sol = object->senderObjects;
+	if ( sol ) {
 #ifdef TQT_THREAD_SUPPORT
-	sol->listMutex->lock();
+	    sol->listMutex->lock();
 #endif // TQT_THREAD_SUPPORT
-	if ( sol ) {
 	    oldSender = sol->currentSender;
 	    sol->ref();
 	    sol->currentSender = this;
@@ -2824,9 +2824,9 @@ void TQObject::activate_signal( TQConnectionList *clist, TQUObject *o )
 	        (currentThread && currentThread->threadPostedEventsDisabled()) ||
 	        (currentThread && object->d->ownThread == currentThread)
 	       ) {
-		sol->listMutex->unlock();
+		if (sol) sol->listMutex->unlock();
 		object->tqt_emit( c->member(), o );
-		sol->listMutex->lock();
+		if (sol) sol->listMutex->lock();
 	    }
 	    else {
 		if (object->d->ownThread && !object->d->ownThread->finished()) {
@@ -2847,9 +2847,9 @@ void TQObject::activate_signal( TQConnectionList *clist, TQUObject *o )
 	        (currentThread && currentThread->threadPostedEventsDisabled()) ||
 	        (currentThread && object->d->ownThread == currentThread)
 	       ) {
-		sol->listMutex->unlock();
+		if (sol) sol->listMutex->unlock();
 		object->tqt_invoke( c->member(), o );
-		sol->listMutex->lock();
+		if (sol) sol->listMutex->lock();
 	    }
 	    else {
 		if (object->d->ownThread && !object->d->ownThread->finished()) {