fix #2236 - bag of holding weight

From a bug report, the weight of a non-cursed bag
of holding would be off by 1 when the weight of contents was a multiple
of 2 (for uncursed) or of 4 (for blessed), since the round off handling
added 1 when it shouldn't in those cases.  Mainly noticeable when empty;
the extra 1 unit made it be twice as heavy as it should have been.

     Probably never noticed in actual play.  He has implemented a patch
which shows weights as part of an object's formatted description, making
this stand out.  Supposedly the Vulture's Eye interface also added a
patch like that a farily long time ago; I wonder why nobody using it ever
noticed.  (Maybe the weight was suppressed for bags of holding there?)

doc/fixes34.4

@@ -401,6 +401,7 @@ some actions taken when blind would yield "Wait!  That's a monster!" (for a
 when polymorphed into an opposite sex monster, if you then become a new
 	human while failing to polymorph into something else, you'd be told
 	"you feel like a new man" for female or "a new woman" for male  
+the weight of a non-cursed bag of holding was sometimes off by 1 unit
 
 
 Platform- and/or Interface-Specific Fixes

src/mkobj.c

@@ -1169,20 +1169,16 @@ register struct obj *obj;
 		 *	Bag status	Weight of contents
 		 *	----------	------------------
 		 *	cursed			2x
-		 *	blessed			x/4 + 1
-		 *	otherwise		x/2 + 1
+		 *	blessed			x/4 [rounded up: (x+3)/4]
+		 *	otherwise		x/2 [rounded up: (x+1)/2]
 		 *
 		 *  The macro DELTA_CWT in pickup.c also implements these
 		 *  weight equations.
-		 *
-		 *  Note:  The above checks are performed in the given order.
-		 *	   this means that if an object is both blessed and
-		 *	   cursed (not supposed to happen), it will be treated
-		 *	   as cursed.
 		 */
 		if (obj->otyp == BAG_OF_HOLDING)
 		    cwt = obj->cursed ? (cwt * 2) :
-					(1 + (cwt / (obj->blessed ? 4 : 2)));
+			  obj->blessed ? ((cwt + 3) / 4) :
+					  ((cwt + 1) / 2);
 
 		return wt + cwt;
 	}

src/pickup.c

@@ -57,7 +57,7 @@ STATIC_DCL void FDECL(tipcontainer, (struct obj *));
  */
 #define DELTA_CWT(cont,obj)		\
     ((cont)->cursed ? (obj)->owt * 2 :	\
-		      1 + ((obj)->owt / ((cont)->blessed ? 4 : 2)))
+     (cont)->blessed ? ((obj)->owt + 3) / 4 : ((obj)->owt + 1) / 2)
 #define GOLD_WT(n)		(((n) + 50L) / 100L)
 /* if you can figure this out, give yourself a hearty pat on the back... */
 #define GOLD_CAPACITY(w,n)	(((w) * -100L) - ((n) + 50L) - 1L)