- Added read and write barriers to the actor pointer in the sound channel

structure.
- Fixed: Items which should stay but had an IF_ALWAYSPICKUP flag were removed.
- Fixed: The pickup flash must only play when an item is picked up so the 
  correct place to spawn it is in AInventory::Touch, not in AInventory::GoAway.


SVN r1278 (trunk)

src/dobjgc.cpp

@@ -300,6 +300,7 @@ static void MarkRoot()
 	DThinker::MarkRoots();
 	FCanvasTextureInfo::Mark();
 	Mark(DACSThinker::ActiveThinker);
+	S_MarkSoundChannels();
 	// Mark dead bodies.
 	for (i = 0; i < BODYQUESIZE; ++i)
 	{