[Bug 2034758] Review Request: apptainer - new name for singularity

https://bugzilla.redhat.com/show_bug.cgi?id=2034758

--- Comment #22 from Maxwell G  ---
> An automated issue is detected about packaging not using hardened build. I think this is a false positive, since nothing is undefining _hardened_build, but I'll check in the next days. I want to check especially if `%undefine _debugsource_packages` is causing this. In fact, I don't see -PIC or -PIE in the applied build flags.

Try adding `%set_build_flags` to the beginning of `%build` and see if that
fixes it.