[build.yml] Overhaul a bit

[Olf0]

• 4.3.0.12 is sufficient to run on 4.5.0 (and 4.6.0, I believe), but also runs on … 4.3.0 and 4.4.0.
• Call mb2 with -d option to generate a separate debug RPM files (instead of embedding debug information into binaries packaged in regular RPM files).
• Build i486 first, because that is the fastest (it is the host's architecture), an if it fails … (have not checked if the whole matrix fails, then, but would assume so; maybe it needs some attribute to do so, maybe it already does and would need an attribute not to do so).
• Do not run docker --privileged without reason!
• Omit explicit pulling of docker image, docker run does that implicitly when the image is not locally available.
• Enhance logging / debug output by calling shells with -x option.
• Simplify and slightly improve shell script.

[Olf0]

@vasvlad, please perform a test build triggered by setting a v* tag after merging this: I hope my spec file changes and these changes are fine, but better check before we proceed with (/ to) the next round of changes.

Thanks!

[Olf0]

Oh, is sailfishos the right branch? I know that spec file changes for SailfishOS should go there, and the build.yaml file is also SailfishOS-specific, but you seem to have maintained the build.yaml file in master.

I just tried switching the base branch from sailfishos to master, which logically results in a huge back-merging of ~ 1300 commits. I think I should have re-based at this point, but I am not at all a Git expert, hence I rather leave it to you to merge this PR into the right branch.

^{As a last resort, I can copy&paste the altered build.yaml file into a new PR to master: Please tell me, if you prefer that.}

[vasvlad]

Hi. File build.yml must be in main branch (IMHO)

[Olf0]

File build.yml must be in main branch (IMHO)

That is fine for now, because the branch sailfishos is the only maintained one. But as soon as there is another active branch, you likely want separate build.yml files for each branch, because they might use different compilers (the Sailfish-SDK is only suited for targetting SailfishOS), need different packaging (e.g. RPM files, DPGK files) etc.

IIRC this can be handled with GitHub-CI/CD-workflows, but I forgot how to configure this in detail. Let us determine that when needed, GitHub's documentation is good and they still develop these mechanisms further (i.e. things may change or new features may become added).