Fix bootstrap failure on all 64-bit hosts

[Mike Stump]

On Friday, May 21, 2004, at 12:27  PM, Zack Weinberg wrote:
> I can reproduce it on x86-64-linux, too.  I really thought we had
> PCH-safe pointer hash tables

Nope.  To be specific, some data structures recompute the hashes and 
repopulate the hash tables, some, never make it into the PCH file, and 
the last group, use hashes that avoid address dependencies.

Also, we want to move in the direction of never repopulating hash 
tables.  The work done is dependent upon the size of the header, and 
the entire point of PCH is to reduce that to an almost constant term.