if pointers are 64 bits and U32 32 bits,
bad things may happen, or at least warnings issued.
p4raw-id: //depot/perl@11949
* which may or may not check number of children).
*/
-typedef U32 PADOFFSET;
+typedef UV PADOFFSET;
#define NOT_IN_PAD ((PADOFFSET) -1)
#ifdef DEBUGGING_OPS