On Sun, 10 Jan 2016 21:57:21 +0000, Joseph L. Casale wrote:
> For the academic sake only, does a facility exist to defer evaluation
> for this use case?
It would get kinda ugly, but you could re-expand the macro body:
%global foo-bar_dir %{expand:%(ls -d %{_builddir}/%{name}-%{version}/foo-bar-*-baz |grep -o '[^/]*$')}