[MacPorts] #64675: fix libvpx for PowerPC and update ffmpeg accordingly

[MacPorts]

#64675: fix libvpx for PowerPC and update ffmpeg accordingly
-----------------------------+-------------------------------------
  Reporter:  barracuda156    |      Owner:  (none)
      Type:  enhancement     |     Status:  new
  Priority:  Normal          |  Milestone:
 Component:  ports           |    Version:  2.7.1
Resolution:                  |   Keywords:  powerpc, leopard, tiger
      Port:  libvpx, ffmpeg  |
-----------------------------+-------------------------------------

Comment (by barracuda156):

 After more testing, I can sum up current state of things:

 1. PowerPC targets are broken for recent versions of `libvpx`. I can't
 make them work and probably won't try further. **They do work on libvpx
 1.6.1** though, which may be good enough (in particular, ffmpeg port file
 refers specifically to 1.6.1).

 2. **The latest version of libvpx still can be built for PowerPC** (at
 least ppc32, I cannot test ppc64 at the moment since some needed
 dependencies don't build for it), if generic-gnu target is used. It
 appears functional. I have rebuilt ffmpeg with it and was able to encode a
 webm video.

 3. There is a hack to pass darwin- and ppc-specific flags to compiler by
 adding them under `generic-gnu` target in `configure.sh`. I dunno if that
 does more good than bad or if it's a good idea at all. But at least it
 works, and resulting libvpx is functional.

 {{{
 36-47% port -v installed libvpx
 The following ports are currently installed:
   libvpx @1.5.0_0 requested_variants='' platform='darwin 10' archs='ppc'
 date='2022-02-15T17:21:42+0800'
   libvpx @1.6.1_0 requested_variants='' platform='darwin 10' archs='ppc'
 date='2022-02-15T19:15:51+0800'
   libvpx @1.11.0_0 requested_variants='' platform='darwin 10' archs='ppc'
 date='2022-02-17T19:46:03+0800'
   libvpx @1.11.0_1 (active) requested_variants='' platform='darwin 10'
 archs='ppc' date='2022-02-19T04:03:08+0800'
 36-47% port -v installed ffmpeg
 The following ports are currently installed:
   ffmpeg @4.4.1_1+gpl2 requested_variants='+gpl2' platform='darwin 10'
 archs='ppc' date='2022-02-15T18:07:25+0800'
   ffmpeg @4.4.1_1+gpl2+gpl3+nonfree (active)
 requested_variants='+gpl2+gpl3+nonfree' platform='darwin 10' archs='ppc'
 date='2022-02-19T04:48:23+0800'
 }}}

 I made several patches (some of which may be redundant, since initially I
 tried to make ppc targets work) and some changes in port files. At this
 point I would appreciate if somebody is interested to review and test. I
 am no expert here, and honestly don't want to spend more time on this.
 If anyone wants me to test libvpx in some way, I am ready to, but I will
 need a specific instruction on what to do. So far I only tested encoding,
 at that worked.

 Some extra details are in this thread:
 https://trac.macports.org/ticket/64653

 P. S. I also don't understand why `ffmpeg` portfile disables `zimg` and
 `x265` for ppc systems. I have them built for ppc:

 {{{
 36-47% port -v installed x265
 The following ports are currently installed:
   x265 @3.4_0 (active) requested_variants='' platform='darwin 10'
 archs='ppc' date='2021-12-11T21:39:50+0800'
 36-47% port -v installed zimg
 The following ports are currently installed:
   zimg @3.0.3_0 (active) requested_variants='' platform='darwin 10'
 archs='ppc' date='2022-01-28T20:40:51+0800'
 36-47% port -v installed libsdl2
 The following ports are currently installed:
   libsdl2 @2.0.3_0 (active) requested_variants='' platform='darwin 10'
 archs='ppc' date='2022-02-14T20:01:16+0800'
 }}}

 `libsdl2` also builds, even though an older version.

-- 
Ticket URL: <https://trac.macports.org/ticket/64675#comment:5>
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