- more cleanup on portal implementation:

- store portal data in a separate structure.
- store portal data in savegames because some of this will be changeable later.
- run a cleanup pass after all portals have been created to weed out broken ones.
- add a definition type that's compatible with Eternity Engine's line portal types.
- swapped arg[2] and arg[3] of Line_SetPortal, because the type is more significant than the alignment.

src/p_saveg.cpp

@@ -53,6 +53,7 @@
 #include "p_lnspec.h"
 #include "p_acs.h"
 #include "p_terrain.h"
+#include "portal.h"
 
 static void CopyPlayer (player_t *dst, player_t *src, const char *name);
 static void ReadOnePlayer (FArchive &arc, bool skipload);
@@ -474,6 +475,12 @@ void P_SerializeWorld (FArchive &arc)
 		}
 		arc << li->args[1] << li->args[2] << li->args[3] << li->args[4];
 
+		if (SaveVersion >= 4532)
+		{
+			arc << li->portalindex;
+		}
+		else li->portalindex = UINT_MAX;
+
 		for (j = 0; j < 2; j++)
 		{
 			if (li->sidedef[j] == NULL)
@@ -508,6 +515,15 @@ void P_SerializeWorld (FArchive &arc)
 	{
 		arc << zn->Environment;
 	}
+
+	if (SaveVersion >= 4532)
+	{
+		arc << linePortals;
+	}
+	else
+	{
+		linePortals.Clear();
+	}
 }
 
 void extsector_t::Serialize(FArchive &arc)