Reduce the amount of gold laying on the floor

There's far too much gold just laying around on the floor.
Didn't previous adventurers grab most of it?

This should incentivize gold detection and digging out vaults,
selling stuff to the shopkeeps, and making it harder to donate
for protection.

Most radical reduction on the first few levels, for dlevel 1,
average amount of gold was 80, is now 10, for dlevel 2, 95->15

Does not change the amount of gold deposited by mineralize,
in the vaults, or contained in chests and large boxes.

doc/fixes36.1

@@ -469,6 +469,7 @@ assigning a type name to a potion on the floor which is actually a mimic could
 with perm_invent option enabled and no inventory, 'i' put up an empty menu
 charisma affects the leeway in demon lord bribes
 make Vlad slightly tougher
+reduce the amount of gold laying on the floor
 
 
 Fixes to Post-3.6.0 Problems that Were Exposed Via git Repository

src/mkobj.c

@@ -1418,8 +1418,10 @@ int x, y;
 {
     register struct obj *gold = g_at(x, y);
 
-    if (amount <= 0L)
-        amount = (long) (1 + rnd(level_difficulty() + 2) * rnd(30));
+    if (amount <= 0L) {
+        long mul = rnd(30 / max(12-depth(&u.uz), 2));
+        amount = (long) (1 + rnd(level_difficulty() + 2) * mul);
+    }
     if (gold) {
         gold->quan += amount;
     } else {