fix #K965 - dropped fragile items don't break

when the drop is being caused by encumbrance or punishment triggering
a fall while going down stairs.

Also, remove a couple instances of 'if (obj==GOLD) contexl.botl=TRUE'
when dropping gold.  They were held over from the obsolete !GOLDOBJ
configuration.  Both are immediately followed by freeinv() which
calls freeinv_core() whichs starts off by setting the botl flag when
taking gold out of inventory.

doc/fixes37.0

@@ -175,6 +175,8 @@ after "double trouble", cloned Wizard would wait until he had suffered some
 	damage or hero moved into direct view; keep STRAT_WAIT for original
 	Wizard but avoid that for clones
 beyond turn 100000, prayer timeout is longer (scaling with game length)
+falling while going down stairs and dropping items due to encumbrance or
+	punishment wasn't subject fragile ones to breakage
 
 
 Fixes to 3.7.0-x Problems that Were Exposed Via git Repository

src/ball.c

@@ -980,12 +980,13 @@ litter()
 
     for (otmp = g.invent; otmp; otmp = nextobj) {
         nextobj = otmp->nobj;
-        if ((otmp != uball) && (rnd(capacity) <= (int) otmp->owt)) {
+        if (otmp != uball && rnd(capacity) <= (int) otmp->owt) {
             if (canletgo(otmp, "")) {
                 You("drop %s and %s %s down the stairs with you.",
                     yname(otmp), (otmp->quan == 1L) ? "it" : "they",
                     otense(otmp, "fall"));
-                dropx(otmp);
+                freeinv(otmp);
+                hitfloor(otmp, FALSE);
                 encumber_msg(); /* drop[xyz]() probably ought to to this... */
             }
         }

src/do.c

@@ -647,9 +647,6 @@ register struct obj *obj;
                 ELevitation = W_ART; /* other than W_ARTI */
             if (flags.verbose)
                 You("drop %s.", doname(obj));
-            /* Ensure update when we drop gold objects */
-            if (obj->oclass == COIN_CLASS)
-                g.context.botl = 1;
             freeinv(obj);
             hitfloor(obj, TRUE);
             if (levhack)
@@ -670,9 +667,6 @@ void
 dropx(obj)
 register struct obj *obj;
 {
-    /* Ensure update when we drop gold objects */
-    if (obj->oclass == COIN_CLASS)
-        g.context.botl = 1;
     freeinv(obj);
     if (!u.uswallow) {
         if (ship_object(obj, u.ux, u.uy, FALSE))

src/dothrow.c

@@ -440,7 +440,7 @@ boolean verbose;
 }
 
 /* Object hits floor at hero's feet.
-   Called from drop(), throwit(), hold_another_object(). */
+   Called from drop(), throwit(), hold_another_object(), litter(). */
 void
 hitfloor(obj, verbosely)
 struct obj *obj;