*: Bump PORTREVISIONs for math/mpc update to 1.3.1

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.

graphics/opencv: bump consumers after e21578d954550998435c5d6d532e2d5a67398bfe

This was missed in the upgrade of graphics/opencv.

Reported by:	VVD

*/*: bump all consumers after recent boost upgrade

One more small cleanup, forgotten yesterday.
Reported by:	lwhsu

Remove # $FreeBSD$ from Makefiles.

graphics/opencv: update to 4.5.1 -- and make port more easily maintainable

This is a major upgrade from 3.x to 4.x.

Changelog from versions 3.4.1--4.5.1 can be found here:
    https://github.com/opencv/opencv/wiki/ChangeLog

Note: this has explicitely not been added as a new graphics/opencv4 port, but
replaces the
      previous graphics/opencv[3] port. Again, to improve maintainability by not
giving ports
      the option to pick the "wrong one" - this leads however to some abandoned
ports being
      broken.

The port has been greatly simplified:
    * graphics/opencv-core which existed to enable ffmpeg to depend on opencv,
and vice versa
      has been removed. ffmpeg no longer can depend on opencv.

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

Change cmake default behaviour to outsource.

Ports that build out of source now simply can use "USES=cmake"
instead of "USES=cmake:outsource". Ports that fail to build
out of source now need to specify "USES=cmake:insource".

I tried to only set insource where explictely needed.

PR:		232038
Exp-run by:	antoine

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

Fix build on powerpc64.

While here, pet portlint.

Bump PORTREVISION on more opencv consumers due to opencv update

New port: multimedia/chilitags: Robust fiducial markers for augmented reality
and robotics

Approved by:	tcberner (mentor)
Differential Revision:	https://reviews.freebsd.org/D13373