perl: use warnings instead of -w; consistent ordering of use, etc.

perl: use warnings instead of -w; consistent ordering of use, etc.

Per thread at:
https://lists.gnu.org/archive/html/automake-patches/2020-08/msg00009.html

* bin/aclocal.in: use warnings instead of #!...-w;
consistent ordering of basic "use" directives,
then BEGIN block,
then standard modules in ASCII order,
then Automake:: modules (not sort),
finally use vars.
Also sort @ISA lists and use qw(...) in ASCII order.
* bin/automake.in: likewise.
* lib/Automake/ChannelDefs.pm: likewise.
* lib/Automake/Channels.pm: likewise.
* lib/Automake/Condition.pm: likewise.
* lib/Automake/Config.in: likewise.
* lib/Automake/Configure_ac.pm: likewise.
* lib/Automake/DisjConditions.pm: likewise.
* lib/Automake/FileUtils.pm: likewise.
* lib/Automake/General.pm: likewise.
* lib/Automake/Getopt.pm: likewise.
* lib/Automake/Item.pm: likewise.
* lib/Automake/ItemDef.pm: likewise.
* lib/Automake/Language.pm: likewise.
* lib/Automake/Location.pm: likewise.
* lib/Automake/Options.pm: likewise.
* lib/Automake/Rule.pm: likewise.
* lib/Automake/RuleDef.pm: likewise.
* lib/Automake/VarDef.pm: likewise.
* lib/Automake/Variable.pm: likewise.
* lib/Automake/Version.pm: likewise.
* lib/Automake/Wrap.pm: likewise.
* lib/Automake/XFile.pm: remove unnecessary imports of
Carp, DynaLoader, and File::Basename.