Remove obsolete find_skates function

find_skates was still in use for its one intended case, but objdescr_is
has been around for a few years now and can do just as good a job
without having to hardcode the first and last boots in objects[].

include/extern.h

@@ -1876,7 +1876,6 @@ extern void tty_ibmgraphics_fixup(void);
 extern void init_objects(void);
 extern void init_oclass_probs(void);
 extern void obj_shuffle_range(int, int *, int *);
-extern int find_skates(void);
 extern boolean objdescr_is(struct obj *, const char *);
 extern void oinit(void);
 extern void savenames(NHFILE *);

src/hack.c

@@ -2058,13 +2058,11 @@ slippery_ice_fumbling(void)
     boolean on_ice = !Levitation && is_ice(u.ux, u.uy);
 
     if (on_ice) {
-        static int skates = 0;
+        if ((uarmf && objdescr_is(uarmf, "snow boots"))
-
+            || resists_cold(&g.youmonst) || Flying
-        if (!skates)
+            || is_floater(g.youmonst.data) || is_clinger(g.youmonst.data)
-            skates = find_skates();
+            || is_whirly(g.youmonst.data)) {
-        if ((uarmf && uarmf->otyp == skates) || resists_cold(&g.youmonst)
+            pline("skates!");
-            || Flying || is_floater(g.youmonst.data)
-            || is_clinger(g.youmonst.data) || is_whirly(g.youmonst.data)) {
             on_ice = FALSE;
         } else if (!rn2(Cold_resistance ? 3 : 2)) {
             HFumbling |= FROMOUTSIDE;

src/o_init.c

@@ -341,21 +341,6 @@ objdescr_is(struct obj* obj, const char * descr)
     return !strcmp(objdescr, descr);
 }
 
-/* find the object index for snow boots; used [once] by slippery ice code */
-int
-find_skates(void)
-{
-    register int i;
-    register const char *s;
-
-    for (i = SPEED_BOOTS; i <= LEVITATION_BOOTS; i++)
-        if ((s = OBJ_DESCR(objects[i])) != 0 && !strcmp(s, "snow boots"))
-            return i;
-
-    impossible("snow boots not found?");
-    return -1; /* not 0, or caller would try again each move */
-}
-
 /* level dependent initialization */
 void
 oinit(void)