fix(rpm): debuginfo support on some distributions

[rdesgroppes]

This enables RPM debuginfo package generation across different Linux distributions (tested on Rocky and Ubuntu in CI) by implementing RPM version-based detection if possible, and falling back to the existing OS release-based detection otherwise.

RPM 4.18.0 introduced changes to make %{buildsubdir} independent of the %setup macro:

• commit: Make %{buildsubdir} more independent of %setup (rpm-software-management/rpm@6caca84c904423)
• since: rpm-4.18.0-alpha1
• release: https://rpm.org/wiki/Releases/4.18.0

While this change enabled setting buildsubdir as a regular macro rather than a spec object property, it had the side effect of altering the relative path handling in install scripts.

This requires different file path formats in the %install section:

• RPM < 4.18, corresponding to the project's "centos" type:

  cp 'bazel-out/k8-fastbuild/bin/tests/rpm/test_debuginfo' '%{buildroot}/test_debuginfo'
  

• RPM >= 4.18, corresponding to the project's "fedora" type:

  cp '../bazel-out/k8-fastbuild/bin/tests/rpm/test_debuginfo' '%{buildroot}/test_debuginfo'
  

Using the wrong "type" causes build failures:

• "fedora" with RPM < 4.18:

  cp: cannot stat '../bazel-out/k8-fastbuild/bin/tests/rpm/test_debuginfo': No such file or directory
  

• "centos" with RPM >= 4.18:

  rm: refusing to remove '.' or '..' directory: skipping '.'
  

The present change therefore implements version detection to automatically select the appropriate "type".

Additional fixes for cross-distribution compatibility

RedHat distros have redhat-rpm-config with %_enable_debug_packages that auto-invokes %debug_package (rpm-software-management/rpm#2204).
Debian/Ubuntu ship vanilla upstream RPM without this configuration:

output 'tests/rpm/test_debuginfo_rpm-debuginfo-1-0..rpm' was not created

That's why the change adds %debug_package only when applicable:

• %{!?_enable_debug_packages:%debug_package}.

Also, since RPM 4.14, unique debug package filenames are enabled by default, leading to variadic filenames being generated:

Executing tests from //tests/rpm:test_golden_debuginfo_rpm_contents
-----------------------------------------------------------------------------
29c29
< /usr/lib/debug/test_debuginfo-1-0.x86_64.debug
---
> /usr/lib/debug/test_debuginfo.debug
FAIL: files "tests/rpm/test_debuginfo_rpm_contents.txt" and "tests/rpm/test_debuginfo_rpm_contents.txt.golden" differ

That's why the change makes debug package filenames consistent across distributions by means of:

• %undefine _unique_debug_names (safe no-op on older RPM versions).

Note: I also verified the change locally with:

• RPM 4.17.1 on Fedora 35 ("centos" type)
• RPM 4.18.2 on Ubuntu 24.04.3 ("fedora" type)
• RPM 4.19.1.1 on Fedora 40 ("fedora" type)

[cgrindel]

The change looks reasonable to me. However, there appear to be some CI failures.

[cgrindel]

LGTM. @aiuto Would you like to take a look?

[aiuto]

@kellyma2 IIRC, you're the only one who knows about rpm debug.

[aiuto]

@meteorcloudy Can you make @kellyma2 part of the project so we can more accurately assign things to him.
He's the defacto rpm expert

[kellyma2]

@kellyma2 IIRC, you're the only one who knows about rpm debug.

I in touch with @rdesgroppes to get some understanding of the details. Will re-look at this.

[kellyma2]

Looks good to me

[meteorcloudy]

Should we move rules_pkg to bazel-contrib?

[rdesgroppes]

Is action expected from me?

[cgrindel]

Now that @kellyma2 has approved. I will merge.