[ng] config.h.{bot,top}: don't support anymore (distribution and deps)

[ng] config.h.{bot,top}: don't support anymore (distribution and deps)

The use of those files have been obsoleted since Autoconf commit 5047ea80
of 1994-08-09, "support alternate input file names"; yes, the "1994" in
there is not a typo: those files were already deprecated in Autoconf 2.0.
It's well past time to remove support for them!

For more information, see chapter "Obsolete Constructs", section
"acconfig.h" of the Autoconf manual.  See also the discussion on automake
bug#7919, in particular the message <http://debbugs.gnu.org/7819#20>.

* NG-NEWS: Update.
* automake.in (handle_configure): Don't automatically distribute the
'config.h.top' and 'config.h.bot' files if they exist, and don't add
them to the '%FILES%' transform when processing the 'remake-hdr.am'
Makefile fragment.  In fact, drop the '%FILES%' transform altogether,
since now it would always expand to empty.
(@common_sometimes): Don't list 'config.h.top' and 'config.h.bot'
anymore.
* lib/am/remake-hdr.am (%CONFIG_HIN%): Don't depend on '%FILES%'
anymore.  That transform has been removed now (and wouldn't be needed
anyway).
* t/autodist-config-headers.sh: Remove as obsolete.

Signed-off-by: Stefano Lattarini <stefano.lattarini@gmail.com>