Homebrew builds now dependencies from sources on unsupported macOSes
(which is 11 now), which makes it slow. Relevant snippet from brew output:
```
Warning: You are using macOS 11.
We (and Apple) do not provide support for this old version.
It is expected behaviour that some formulae will fail to build in this old version.
It is expected behaviour that Homebrew will be buggy and slow.
```
SDL2 now obviously works on U20.04, because we are building there. It
doesn't work on U22.04, but neither the build with SDL 2.0.20 nor 2.26.2
does.
The problem seems actually to be the inclusion of Wayland libraries in
AppImage.
Used msys/curl instead of clang64/mingw-w64-clang-x86_64-curl for the
upload.
For whatever reason, the other curl variant ceased to collaborate with
GitHub, see failed run (and subsequent ones):
https://github.com/CESNET/UltraGrid/actions/runs/4223917061/jobs/7334218587
I didn't manage to reproduce it on a local Windows machine so there is
perhaps some hidden factor present.
This change is just a workaround and should be removed when not needed.
It seems like that changing arbitrary packages installed (dependencies
for SDL) cause some FFmpeg dependencies to be rebuild (libvpx, SVT-*).
So revert back to depending on whole .github/scripts/Linux/prepare.sh
but move building/installation of AJA, live555 etc. to separate file
to reduce cached FFmpeg rebuilds at least a bit.
+ removed chmod 777 /usr/local
The file with dependencies installation is a prerequisity for FFmpeg
rebuild so move it to a smaller file to reduce number of required FFmpeg
rebuilds if that file changes.
Install libopencv-core-dev instead of libopencv-dev because it
transitively (libopencv-highgui-dev) depend on libswscale-dev that is
going to be removed.
- check appimage with Arch and --capabilities - this catches segfault
with incompatible jack implementation in bundle and system
(pipewire-jack package needed)
- use empty directory for container build (instead of ".") also for
Ubuntu (would not needlessly copy contents of current directory to
Docker daemon)
Upload result to release artifacts also when scheduled in main repo
(github.ref != 'refs/heads/arm-build').
+ do not repeat the inverted condition but rather upload the artifact
if release artefact was not uploaded
