the date
it inserts in the version string is the date of compilation that
provides no help to reproduce the bug. Is it possible to replace it
with the date of the last CVS checkout/update that says exactly what
state of the code repository contains the bug?
Everything's possible -- this is software. You could write code that
looks in the ChangeLog files for the latest log entries in src/,
lisp/, and leim/, for example. Or the code could look at the time
stamp of some CVS/Template file (in any directory) -- but this needs
to be changed for those who use VCs other than CVS, and for everybody
when we switch to bzr.
Personally, I never build without "cvs update", so the build time is
almost exactly the checkout time.