tools: Commit autoconf output from Debian buster

tools: Commit autoconf output from Debian buster

These files are in tree so that people can build (including from git)
without needing recent autotools.

We should update them periodically.  Debian buster has been Debian
stable fopr a while.  Our CI is running buster.

There should be no significant functional change; it's possible that
there are bugfixes to the configure scripts but I have not reviewed
them.

These files were last changed in
  83c845033dc8bb3a35ae245effb7832b6823174a
  libxl: use vchan for QMP access with Linux stubdomain
where a new feature was added.  However, that commit contains a lot of
extraneous noise in configure compared to its parent.

Compared to 83c845033dc8bb3a35ae245effb7832b6823174a~, this commit
restores those extraneous changes, leaving precisely the correct
changes.  So one way of looking at the changes we are making now, is
that we are undoing accidental changes to the autoconf output.

I used Debian's autoconf 2.69-11 on amd64.

CC: Wei Liu <wl@xen.org>
CC: Nick Rosbrook <rosbrookn@gmail.com>
Reported-by: Nick Rosbrook <rosbrookn@gmail.com>
CC: Paul Durrant <paul@xen.org>
Signed-off-by: Ian Jackson <ian.jackson@eu.citrix.com>
Reviewed-by: Anthony PERARD <anthony.perard@citrix.com>
Release-acked-by: Paul Durrant <paul@xen.org>