Adding support for FFmpeg in UWP.

[khouzam]

This enables ffmpeg to be compiled as a UWP as well as a desktop app.

Adding support to download gas-preprocessor as an acquire_program.
Update all packages when installing msys2
Download perl and gcc for ARM assembly in ffmpeg through msys (for gas-preprocessor.pl).

[msftclas]

@khouzam,
Thanks for your contribution as a Microsoft full-time employee or intern. You do not need to sign a CLA.
Thanks,
Microsoft Pull Request Bot

[bagong]

Any hope for a working static build for the windows platform? 😄 (portability)

[khouzam]

I might have some time to take a look at that

[bagong]

That would be really appreciated!!! 😄 I just built an app with ffmpeg static and was surprised it didn't run, until I realized it still needed access to the "static ffmpeg dlls" ;)

[ras0219-msft]

Thanks for the PR, @khouzam!

I pushed a few changes to your branch (bump the version number and hopefully fix the libcmt thing).

For some reason, my arm-uwp builds fail with:

:: Synchronizing package databases...
 mingw32 is up to date
 mingw64 is up to date
 msys is up to date
 there is nothing to do
=== CONFIGURING ===
GNU assembler not found, install/update gas-preprocessor

If you think configure made a mistake, make sure you are using the latest
version from Git.  If the latest version fails, report the problem to the
ffmpeg-user@ffmpeg.org mailing list or IRC #ffmpeg on irc.freenode.net.
Include the log file "config.log" produced by configure as this will help
solve the problem.

Any ideas?

[khouzam]

Hi @ras0219-msft

Can you share the config.log in the ffmpeg arm build?

[khouzam]

I've reproed the issue, the system is not installing gcc & perl for MSYS properly.

Reverting these lines in the ffmpeg portfile makes it run again:

        vcpkg_execute_required_process(
            COMMAND ${BASH} --noprofile --norc -c "PATH=/usr/bin:\$PATH;pacman -Sy --noconfirm --needed perl gcc"
            WORKING_DIRECTORY ${CURRENT_BUILDTREES_DIR}
            LOGNAME msys-${TARGET_TRIPLET}

[khouzam]

Ok I fixed the issue. Switching from double quotes to single quotes makes bash happy again.

[ras0219-msft]

Thanks a ton @khouzam :)