* aclocal.in: Use Automake::ChannelDefs, and adjust all output

* aclocal.in: Use Automake::ChannelDefs, and adjust all output
to be done via `fatal', `msg', `verb', or `prog_error'.
(version): New function.
(parse_arguments): Rewrite using Getopt::Long, call &version, and
honor -W and --warning.
($verbose): Remove.
(trace_used_macros): Do not trace the first arguments of macros
for which we do not need it.  This caused failures because of
unexpected newlines in the output.
* doc/automake.texi (aclocal options): Document -W and --warning.
* tests/defs.in (ACLOCAL): Always use -Werror, to catch Perl
warnings about uninitialized variables.