Having these in the sysconf log can be helpful when triaging test
failures from users.
* t/get-sysconf.sh: Log autoconf & libtoolize version.
# happen with older perl installation, or on MinGW/MSYS.
$PERL -e 'use TAP::Parser; print $TAP::Parser::VERSION, "\n"' || :
+$AUTOCONF --version
+$AUTOCONF --help
+libtoolize --version
+libtoolize --help
+
# It's OK if the selected Lex and Yacc programs don't know how to print
# the version number or the help screen; those are usually available only
# for Flex and Bison.