[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):

 There is some success towards this end. I was able to build the latest
 version of libvpx for generic-gnu target, rebuild ffmpeg with it and
 verify it actually can encode a webm video file.


 {{{
 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 (active) requested_variants='' platform='darwin 10'
 archs='ppc' date='2022-02-17T19:46:03+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='2022-02-17T20:21:06+0800'
 }}}

 At the moment ppc-specific targets remain broken.

-- 
Ticket URL: <https://trac.macports.org/ticket/64675#comment:3>
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