fix #Q382 - jumping possible while riding a sleeping pet (trunk only)

From a bug report:  when riding,
#jump command and jumping spell didn't check whether steed is able to move.
This makes #jump command, either magic boots or knight's innate ability,
fail if the steed can't move.  Spell still succeeds; its magic overrides
steed's immobility.  Fix is trunk only since it relies on a function that
isn't in the branch.

     Also, tweak hero movement to avoid an extra function call per move
when not riding.

doc/fixes35.0

@@ -187,6 +187,7 @@ monsters can use ranged attacks over/around boulders, same as hero
 can't drop part of a stack of N weapons welded to hero's hand
 pickup still accepts m as command prefix, but now rejects F,g,G,M,numpad 5
 scatter piles of kicked gold rather than move the entire pile at once
+#jump attempt fails if mounted on sleeping steed; jumping spell still works
 
 
 Platform- and/or Interface-Specific Fixes

src/apply.c

@@ -1332,6 +1332,12 @@ int magic; /* 0=Physical, otherwise skill level */
 	} else if (!magic && !Jumping) {
 		You_cant("jump very far.");
 		return 0;
+#ifdef STEED
+	/* if steed is immobile, can't do physical jump but can do spell one */
+	} else if (!magic && u.usteed && stucksteed(FALSE)) {
+		/* stucksteed gave "<steed> won't move" message */
+		return 0;
+#endif
 	} else if (u.uswallow) {
 		if (magic) {
 			You("bounce around a little.");

src/hack.c

@@ -1,4 +1,4 @@
-/*	SCCS Id: @(#)hack.c	3.5	2006/08/09	*/
+/*	SCCS Id: @(#)hack.c	3.5	2007/02/10	*/
 /* Copyright (c) Stichting Mathematisch Centrum, Amsterdam, 1985. */
 /* NetHack may be freely redistributed.  See license for details. */
 
@@ -1221,7 +1221,7 @@ domove()
 	}
 	/* not attacking an animal, so we try to move */
 #ifdef STEED
-	if ((u.dx || u.dy) && stucksteed(FALSE)) {
+	if ((u.dx || u.dy) && u.usteed && stucksteed(FALSE)) {
 		nomul(0);
 		return;
 	}