Make REINCARNATION unconditional.

There is a lot of code affected by this, and Pat Rankin correctly
observes that it would be better to store roguelike as a level flag
rather than just using Is_rogue_level. A note for the future.

include/dungeon.h

@@ -232,9 +232,7 @@ typedef struct mapseen  {
 	    Bitfield(valley, 1);
 	    Bitfield(msanctum, 1);
 	    Bitfield(ludios, 1);
-# ifdef REINCARNATION
 	    Bitfield(roguelevel, 1);
-# endif
 	} flags;
 	/* custom naming */
 	char *custom;