[MacPorts] #64469: ffmpeg-devel @5.0: buildbot failures for 10.9 through 10.11

[MacPorts]

#64469: ffmpeg-devel @5.0: buildbot failures for 10.9 through 10.11
---------------------------+--------------------------
 Reporter:  mascguy        |      Owner:  mascguy
     Type:  defect         |     Status:  assigned
 Priority:  Normal         |  Milestone:
Component:  ports          |    Version:  2.7.1
 Keywords:  patch-pending  |       Port:  ffmpeg-devel
---------------------------+--------------------------
 For this new release of FFMpeg, buildbot builds are failing with two
 different compilation errors.

 https://ports.macports.org/port/ffmpeg-devel/builds/

 For 10.11, the failure relates to `__builtin_available`:

 {{{
 libavutil/hwcontext_videotoolbox.c:420:13: error: use of unknown builtin
 '__builtin_available' [-Wimplicit-function-declaration]
         if (__builtin_available(macOS 10.11, iOS 9, *))
             ^
 }}}

 However, for 10.9 and 10.10, we're seeing the following:

 {{{
 libavcodec/videotoolbox.c:907:13: error: implicit declaration of function
 'VTRegisterProfessionalVideoWorkflowVideoDecoders' is invalid in C99
 [-Werror,-Wimplicit-function-declaration]
             VTRegisterProfessionalVideoWorkflowVideoDecoders();
             ^
 }}}

 The following upstream patch may fix both issues, as they appear to be
 related:

 https://www.mail-archive.com/ffmpeg-devel@ffmpeg.org/msg128213.html

 Need to test locally, to validate whether said patch solves the issue.

-- 
Ticket URL: <https://trac.macports.org/ticket/64469>
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