multimedia/qt6-multimedia: respect upstream defaults

Expose auto-detected dependencies as options to make builds deterministic.
Disabling all audio backends is forbidden to avoid crashes as upstream
doesn't test a configuration that cannot happen on Android, macOS, Windows,
QNX or desktop Linux (except Gentoo).

PR:		268876
Approved by:	portmgr blanket, maintainer timeout (partially: no patch but no
help)

Qt: Update Qt 6 to 6.4.2

As a patch release, Qt 6.4.2 does not introduce any new features but
contains ~ 150 bug fixes, security updates, and other improvements to
the top of the Qt 6.4.1 release. See more information about the most
important changes and bug fixes from Qt 6.4.2 release note.

Announcement:	https://www.qt.io/blog/qt-6.4.2-released
Release
Notes:	https://code.qt.io/cgit/qt/qtreleasenotes.git/about/qt/6.4.2/release-note.md

multimedia/qt6-multimedia: fix build on powerpc

No AltiVec on powerpc:
In file included from
/wrkdirs/usr/ports/multimedia/qt6-multimedia/work/qtmultimedia-everywhere-src-6.4.1/src/3rdparty/pffft/pffft.c:107:
/usr/lib/clang/13.0.0/include/altivec.h:13:2: error: "AltiVec support not
enabled"

multimedia/qt6-multimedia: fix build on powerpc64

In file included from
/wrkdirs/usr/ports/multimedia/qt6-multimedia/work/qtmultimedia-everywhere-src-6.4.1/src/resonance-audio/../3rdparty/eigen/Eigen/Core:210:
/wrkdirs/usr/ports/multimedia/qt6-multimedia/work/qtmultimedia-everywhere-src-6.4.1/src/resonance-audio/../3rdparty/eigen/Eigen/src/Core/arch/AltiVec/PacketMath.h:1345:32:
error: use of undeclared identifier 'vec_sqrt'; did you mean 'vec_rsqrt'?
  BF16_TO_F32_UNARY_OP_WRAPPER(vec_sqrt, a);
                               ^~~~~~~~
                               vec_rsqrt
/wrkdirs/usr/ports/multimedia/qt6-multimedia/work/qtmultimedia-everywhere-src-6.4.1/src/resonance-audio/../3rdparty/eigen/Eigen/src/Core/arch/AltiVec/PacketMath.h:1302:22:
note: expanded from macro 'BF16_TO_F32_UNARY_OP_WRAPPER'
  Packet4f op_even = OP(a_even);\
                     ^
/usr/lib/clang/13.0.0/include/altivec.h:8472:34: note: 'vec_rsqrt' declared here
static vector float __ATTRS_o_ai vec_rsqrt(vector float __a) {

Qt: Update Qt6 to 6.4.1

Qt 6.4.1 release is a patch release made on the top of Qt 6.4.0.  As a
patch release, Qt 6.4.1 does not add any new functionality but provides
bug fixes and other improvements and maintains both forward and backward
compatibility (source and binary) with Qt 6.4.0.

For detailed information about Qt 6.4, refer to the online documentation
included in this distribution. The documentation is also available
online:

https://doc.qt.io/qt-6/index.html

Changelog:
https://code.qt.io/cgit/qt/qtreleasenotes.git/about/qt/6.4.1/release-note.md

Qt: Update Qt6 to 6.4.0

Relase Notes: https://www.qt.io/blog/qt-6.4-released

QT: Update Qt 6 to 6.3.2

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.

multimedia/qt6-multimedia: new port

This adds the missing Qt 6 multimedia module to the tree.

As with the rest of the Qt 6 ports, we first need to figure
out what is actually required by other ports before we can
finalize them.