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

Remove # $FreeBSD$ from Makefiles.

archivers/zip-ada: archivers/zip-ada: Update to 55.

Approved by:	tcberner (mentor)
Differential Revision:	https://reviews.freebsd.org/D19223

Add EXAMPLES options to ports that should have one.

Also various fixes related to said option.

PR:		230864
Submitted by:	mat
exp-runs by:	antoine

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

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

archivers/zip-ada: Upgrade version 51 => 52

Several new programs were identified and installed.

archivers/zip-ada: Upgrade version 50_f1 => 51

archivers/zip-ada: set portscout to ignore 50_f1

Zip-ada moved to version 50_f1 using a PORTREVISION bump and portscout
doesn't know how to deal with it.  Just ignore the version to clear the
false positive.

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).

archivers/zip-ada: Delta upgrade to version 50

A "f1" version of version 50 was released, so keep the same
version number but change tarball and bump portrevision.

archivers/zip-ada: Upgrade version 49 => 50

archivers/zip-ada: Upgrade version 48 => 49

A few more tools and examples came in.  The build instruction was
unmasked, listed were put into alphabetical order.  The static library
in now installed with INSTALL_DATA because INSTALL_LIB will strip the
symbols and this causes issues on Ada libraries.

archivers/zip-ada: Unmask install commands and remove @dirrm lines

archivers/zip-ada: Upgrade version 46 => 48

Convert archivers to USES=zip

Convert from USE_DOS2UNIX to USES=dos2unix

archivers/zip-ada: Update from version 45 to 46

archivers/zip-ada: Convert to staging

Also remove extract depends on unzip; base tar can do this.

Add NO_STAGE all over the place in preparation for the staging support (cat:
archivers)

florist-gpl, zip-ada: Add trailing slash for WWW field.

These trailing slashes may be required as web site does not appear on
FreshPorts entries.

Approved by:	bapt/culot (mentors, implicit)

Add new port: archivers/zip-ada

The Zip-Ada library is written entirely in Ada, allowing compression
operations without any OS-dependent external calls on streams and files.

Approved by:	bapt/culot (mentors, implicit)