[MacPorts] #70958: ffmpeg: add libwebp support

[MacPorts]

#70958: ffmpeg: add libwebp support
---------------------------+----------------------
  Reporter:  seamusdemora  |      Owner:  mascguy
      Type:  enhancement   |     Status:  assigned
  Priority:  Normal        |  Milestone:
 Component:  ports         |    Version:  2.10.1
Resolution:                |   Keywords:
      Port:  ffmpeg        |
---------------------------+----------------------

Comment (by ryandesign):

 Replying to [comment:2 seamusdemora]:
 > I should have mentioned that I also installed `webp` using MacPorts...
 but that didn't prevent the error with `ffmpeg`.

 Correct, most ports won't magically use other ports just because you
 install those other ports; usually, if that happens, it would be
 considered a bug. We want ReproducibleBuilds, not builds that change
 depending on what the user already has installed.

 > RE: "already (have) a port for {{{webp}}}". Aye, but I wasn't clear on
 whether or not that included {{{libwebp}}} :)

 You can use `port contents webp` to discover what it installed.

 > I guess I'll have to wait on the maintainers to modify {{{ffmpeg}}} to
 use {{{libwebp}}}...

 Right, the maintainers need to add `port:webp` to `depends_lib`, add `
 --enable-libwebp` to `configure.args`, and increase `revision`. If you
 like, you can try those modifications yourself, and if they work, you can
 submit a pull request.

 We also have ports ffmpeg-devel, ffmpeg6, and ffmpeg7. It is best to keep
 related ports as similar as possible, so ideally webp support would be
 added to all four ports at the same time and in the same way. Currently,
 the ffmpeg7 and ffmpeg-devel ports explicitly disable webp support while
 the ffmpeg and ffmpeg6 ports do not mention webp support.

-- 
Ticket URL: <https://trac.macports.org/ticket/70958#comment:3>
MacPorts <https://www.macports.org/>
Ports system for macOS