Make buildSRPMFromSCM faster?

[drago01]

On Sat, Jul 19, 2014 at 1:30 PM, Richard W.M. Jones <rjones at redhat.com> wrote:
>
> The first step of most Koji builds is buildSRPMFromSCM, where a
> .src.rpm file is built from the git repo.
>
> Currently this involves completely building a mock buildroot
> containing all the BuildRequires, and running `rpmbuild -bs'.  This
> takes many minutes (especially when arm is chosen as a builder).
>
> It seems the reason for this is because the spec file has to be fully
> parsed in order to work out the Source lines.  Since Source lines
> might depend on RPM macros which might depend on any BuildRequire'd
> package,  [...]

For most packages this is not the case (i.e you do not need BR to
build the srpm) ... maybe we should have some way to flag a package as
such?
Maybe just by adding a file with a specific name to the repo?