When to define an external dependent in perl module?

[chenlin rao]

I found <https://metacpan.org/module/Module::Install#requires_external_bin>
. But it can't auto install the `require_external` system packages now.
Another way I thought is pack my perl scripts as rpm and define the require
perl modules as rpm dependment. But not all CPAN module has rpm in yum.repo.
Any help?