remove and transfer INVISIBLE_OBJECTS to branch

src/weapon.c

@@ -183,11 +183,6 @@ struct monst *mon;
 	if (is_pick(otmp) &&
 	   (passes_walls(ptr) && thick_skinned(ptr))) tmp += 2;
 
-#ifdef INVISIBLE_OBJECTS
-	/* Invisible weapons against monsters who can't see invisible */
-	if (otmp->oinvis && !perceives(ptr)) tmp += 3;
-#endif
-
 	/* Check specially named weapon "to hit" bonuses */
 	if (otmp->oartifact) tmp += spec_abon(otmp, mon);