[Heap parent fix
clinton@unknownlamer.org**20090406162020
 Ignore-this: 32865daf7c7b983808dfd9bbdff58592
 Same as the fix in SBCL for heaps larger than 100 elements
] hunk ./timers-bt.lisp 19
-  (ash i -1))
+  (ash (1- i) -1))