zsh-4_2-patches branch

[Paul Ackersviller <pda@xxxxxxxxxxxxxxxx>]

I've finished the back-merging of many bug-fixes onto the 4.2 branch,
as well as most completions (the notable exceptions being 22328 and
23479).  The ChangeLog on the branch should match the changes committed
to the branch, but I wouldn't be surprised by a mistake or two given
the hundreds of changes I looked at.  I've also sanitized all the
branch's .distfiles using Peter's check_dist_files script.

If anyone cares, I also have the list of change numbers I looked at,
but didn't merge.  These were not all just new features, but some fixes
didn't merge cleanly or compile properly, sometimes only because of
extra parameters on something like zerr().  I didn't attempt to guess
at a resolution for these problems, but left the changes out.