> vc-hg-state-fast might still need 
> attention.  Currently (zerop (lsh -1 32)) returns nil on all platforms, 
> so it's useless; but that might change

This prompted me to audit the uses of lsh in the Emacs source code. I found and 
fixed a few glitches by installing the attached patch; in particular it fixes 
vg-hg-state-fast by using ash instead, as ash's semantics are clear and not 
subject to change. This patch goes further in this direction by replacing lsh 
with ash when either will do.

As this fixes the remaining problems mentioned in this bug report, I'm boldly 
closing the report.