- Move Perl's man1 files along with its man3 files.
- Move where Perl installs its modules man1 pages.
- Convert the ports installing man1 pages.
- Make different Perl versions installable at the same time.
  Though you should note that only the default version can be used to
  install Perl modules, and the non default Perl versions cannot use the
  modules installed via ports if they contain .so as they are installed
  in a version specific directory.

Reviewed by:	bapt (the Mk bits)
Exp-run by:	antoine
Sponsored by:	Absolight
Differential Revision:	https://reviews.freebsd.org/D3542

- Replace ${MASTER_SITE_FOO} with FOO.
- Merge MASTER_SITE_SUBDIR into MASTER_SITES when possible. (This means 99.9%
  of the time.)
- Remove occurrences of MASTER_SITE_LOCAL when no subdirectory was present and
  no hint of what it should be was present.
- Fix some logic.
- And generally, make things more simple and easy to understand.

While there, add magic values to the FESTIVAL, GENTOO, GIMP, GNUPG, QT and
SAMBA macros.

Also, replace some EXTRACT_SUFX occurences with USES=tar:*.

Checked by:	make fetch-urlall-list
With hat:	portmgr
Sponsored by:	Absolight

Before, we had:

  site_perl :           lib/perl5/site_perl/5.18
  site_perl/perl_arch : lib/perl5/site_perl/5.18/mach
  perl_man3 :           lib/perl5/5.18/man/man3

Now we have:

  site_perl : lib/perl5/site_perl
  site_arch : lib/perl5/site_perl/mach/5.18
  perl_man3 : lib/perl5/site_perl/man/man3

Modules without any .so will be installed at the same place regardless of the
Perl version, minimizing the upgrade when the major Perl version is changed.
It uses a version dependent directory for modules with compiled bits.

As PERL_ARCH is no longer needed in plists, it has been removed from
PLIST_SUB.

The USE_PERL5=fixpacklist keyword is removed, the .packlist file is now
always removed, as is perllocal.pod.

The old site_perl and site_perl/arch directories have been kept in the
default Perl @INC for all Perl ports, and will be phased out as these old
Perl versions expire.

PR:		194969
Differential Revision:	https://reviews.freebsd.org/D1019
Exp-run by:	antoine
Reviewed by:	perl@
Approved by:	portmgr