cleanup: Remove ports depending on expired lang/gcc6-aux

Keep ports-mgmt/synth and dependencies (including lang/gcc6-aux itself)
for now as synth is the only Ada port still maintained and might be
somewhat high-profile.

Removed ports:
archivers/zip-ada
cad/ghdl
databases/adabase
databases/apq
databases/apq-mysql
databases/apq-odbc
databases/apq-pgsql
devel/ada-util

graphics/mesa-libs: Bump reverse deps for libglvnd

Per discussion with bapt on helping pkg handle the changing of these
deps and avoiding impossible upgrade senarios.

PR:		246767
Reviewed by:	manu, bapt
Approved by:	x11
Differential Revision:	https://reviews.freebsd.org/D30824

Remove # $FreeBSD$ from Makefiles.

Add USES=xorg USES=gl, ports categories d

Add USES=xorg, USES=gl and in a few cases USES=gnome to ports in categories
starting with 'd'.

Bump PORTREVISIONs of all users of math/mpc that we just updated to
version 1.1.0 (via revision 464079).

Revision bump of all ports with USE_GL after consolidation of mesa-libs

Approved by:	swills (mentor)
Differential Revision:	https://reviews.freebsd.org/D10845

Return ports maintained by John Marino to the pool, he is no longer interested.

Submitted by:	Mark Millard via private e-mail

Return the ports mistakenly reset to ports@ in r433856 to John Marino.

The mistake was completely on my part, I somehow connected the dots the
wrong way in my head.

The only exceptions (for now) are archivers/zstd and ports-mgmt/synth
which were already picked up by new volunteers in the mean time.

Return ports maintained by John Marino to the pool, see r433827 for details

Change Ada Framework foundation from gcc5-aux to gcc6-aux

GCC 6.1 was released this week.  The Ada Framework in FreeBSD ports has
been based on GCC 5.3 GNAT although GCC 6.x has been supported for awhile
via the ADA_DEFAULT option in make.conf.

Now that GCC 6 has been officially released, switch to it by default.
People can maintain the old foundation by putting "ADA_DEFAULT=5" in
/etc/make.conf.

Libraries built by one GNAT are unusable by another, so almost every Ada
port has been bumped as a result.  Noticable exceptions are dns/ironsides
which fails to build on gcc6 (thus USES=ada:5 is set) and cad/ghdl which
needs additional testing as it may require gcc5 on FreeBSD (DragonFly
uses the LLVM backend only).

Replace USES=libtool:oldver with USES=libtool or USES=libtool:keepla in
the 32 ports that still use it.  Bump PORTREVISION on their dependent
ports except the ones that depend on these:

audio/libogg
audio/libvorbis
devel/pcre
ftp/curl
graphics/jpeg
graphics/libart_lgpl
graphics/tiff
textproc/expat2
textproc/libxslt

In these cases the same trick as in the recent gettext update is used.

marino 12 devel ports: Remove @dirrm, tend install commands, plus

The main purpose of this commit is to remove @dirrm from the pkg-plist of
some of my ports in devel category.  While here, also:
  * Unmask some commands
  * Use parenthesis on compound commands for multi-job support
  * Add a license in one case
  * USES=python conversion in one case
  * Add WWW and reformat description in one case
  * Respect 80-columns

Update the default version of GCC in the Ports Collection from GCC 4.7.4
to GCC 4.8.3.

Part II, Bump PORTREVISIONs.

PR:		192025
Tested by:	antoine (-exp runs)
Approved by:	portmgr (implicit)

Convert a bunch of USE_BZIP2 to USES=tar:bzip2

Approved by:	portmgr (not really, but touches unstaged ports)

devel/sdl_gnat: Explicitly listed libsdl as dependency

suggested by:	mva@

Add new port devel/sdl_gnat: Thin Ada bindings for SDL (GPLv3)