graphics/perceptualdiff: drop GCC usage

graphics/perceptualdiff: fix build without libomp

CMake Error at /usr/local/share/cmake/Modules/FindOpenMP.cmake:261
(try_compile):
  Failed to generate test project build system.
Call Stack (most recent call first):
  /usr/local/share/cmake/Modules/FindOpenMP.cmake:537 (_OPENMP_GET_FLAGS)
  CMakeLists.txt:25 (find_package)
This warning is for project developers.  Use -Wno-dev to suppress it.

Remove WWW entries moved into port Makefiles

Commit b7f05445c00f has added WWW entries to port Makefiles based on
WWW: lines in pkg-descr files.

This commit removes the WWW: lines of moved-over URLs from these
pkg-descr files.

Approved by:		portmgr (tcberner)

Add WWW entries to port Makefiles

It has been common practice to have one or more URLs at the end of the
ports' pkg-descr files, one per line and prefixed with "WWW:". These
URLs should point at a project website or other relevant resources.

Access to these URLs required processing of the pkg-descr files, and
they have often become stale over time. If more than one such URL was
present in a pkg-descr file, only the first one was tarnsfered into
the port INDEX, but for many ports only the last line did contain the
port specific URL to further information.

There have been several proposals to make a project URL available as
a macro in the ports' Makefiles, over time.

all: R eturn sobomax' ports to the pool

Commit bit of sobomax@ was safe-kept on 2018-12-03 by portmgr-secretary@
but somehow the ports were not reset. Reset all the ports except
net/ortp which has been exclusively requested by zirias@

Approved by:	portmgr (blanket)

graphics: remove 'Created by' lines

A big Thank You to the original contributors of these ports:

  *  "Waitman Gobble" <uzimac@da3m0n8t3r.com>
  *  Aaron Dalton <aaron@FreeBSD.org>
  *  Abel Chow <ozsanh45vds001@sneakemail.com>
  *  Adam Weinberger <adamw@FreeBSD.org>
  *  Ade Lovett <ade@FreeBSD.org>
  *  Ade Lovett <ade@lovett.com>
  *  Akinori MUSHA aka knu <knu@idaemons.org>
  *  Aldis Berjoza <aldis@bsdroot.lv>
  *  Alex Hayward <xelah@xelah.com>
  *  Alex Ivasyuv <siegerstein@pochta.ru>
  *  Alex Samorukov <samm@os2.kiev.ua>

Remove # $FreeBSD$ from Makefiles.

Bump PORTREVISION for ports depending on the canonical version of GCC
as defined in Mk/bsd.default-versions.mk which has moved from GCC 8.3
to GCC 9.1 under most circumstances now after revision 507371.

This includes ports
 - with USE_GCC=yes or USE_GCC=any,
 - with USES=fortran,
 - using Mk/bsd.octave.mk which in turn features USES=fortran, and
 - with USES=compiler specifying openmp, nestedfct, c11, c++0x, c++11-lang,
   c++11-lib, c++14-lang, c++17-lang, or gcc-c++11-lib
plus, everything INDEX-11 shows with a dependency on lang/gcc9 now.

PR:		238330

Bump PORTREVISION for ports depending on the canonical version of GCC
defined via Mk/bsd.default-versions.mk which has moved from GCC 7.4 t
GCC 8.2 under most circumstances.

This includes ports
 - with USE_GCC=yes or USE_GCC=any,
 - with USES=fortran,
 - using Mk/bsd.octave.mk which in turn features USES=fortran, and
 - with USES=compiler specifying openmp, nestedfct, c11, c++0x, c++11-lang,
   c++11-lib, c++14-lang, c++17-lang, or gcc-c++11-lib
plus, as a double check, everything INDEX-11 showed depending on lang/gcc7.

PR:		231590

Return currently unmaintained ports to sobomax@ who is still a src committer.

Re-assign sobomax@'s ports after his commit bit was safekept.

More precisely specify USES=compiler to fix build on gcc-based
platforms such as powerpc64.

Tested on powerpc64, amd64.

Approved by:	portmgr (tier-2 blanket)

Fix WWW

Approved by:	portmgr (blanket)

Mark some ports failing on power64.  In cases where the error message
was a stub, provide a real one.

While here, pet portlint.

Approved by:	portmgr (tier-2 blanket)
Reported by:	swills

Fix USE_GITHUB usage.

Sponsored by:	Absolight

Add perceptualdiff, a program that compares two images using a perceptually
based image metric.

We find it pretty useful for automated installation media testing.