Automatically exclude BRs that are excluded by rpm macros

[mbooth101]

I am trying out generate-modulemd.py and think it would be neat if, when enabling build deps, we could automatically exclude BRs that are eliminated when any rpm macro is set.

For example, say we have this spec file:

%bcond_without junit5

BuildRequire: junit
%if %{with junit5}
BuildRequire: junit5
%endif

And in my koschie.cfg I have the following section:

    "macros": {
        "_without_junit5": 1,
    },

Then the script should automatically eliminate junit5 from the dep tree.

For now, I am adding junit5 to the "excludes" list in koschie.cfg manually.

[mizdebsk]

To implement this properly the script would need to rebuild each SRPM in a mock chroot (by rebuilding SRPM I mean rpmbuild -bs --nodeps) . Results need to be cached to avoid having to rebuild the same SRPM every time the script is ran.