Jousting

Players wielding a lance while riding will "joust" monsters
they attack.

Note that monsters don't get pushed into inaccessable tiles such
as walls, doors, iron bars, water, or lava; they stay at the edge.
Further refinements are possible for these cases.

include/extern.h

@@ -425,6 +425,7 @@ E int NDECL(dothrow);
 E int NDECL(dofire);
 E void FDECL(hitfloor, (struct obj *));
 E void FDECL(hurtle, (int,int,int,BOOLEAN_P));
+E void FDECL(mhurtle, (struct monst *,int,int,int,BOOLEAN_P));
 E void FDECL(throwit, (struct obj *,long,BOOLEAN_P));
 E int FDECL(omon_adj, (struct monst *,struct obj *,BOOLEAN_P));
 E int FDECL(thitmonst, (struct monst *,struct obj *));