Build rules_perl for ppc64le.

Hello team,
We are working on building [ray](https://github.com/ray-project/ray) on Power architecture and it has a dependency on rules_perl. There is no perl tarball released for Power by relocatable_perl.
Is there a way to use system installed perl instead of fetching it from relocatable_perl? Any pointers will be helpful. Thank you.

Start by tracing how rules_perl fetches relocatable_perl for ppc64le and review the Bazel build setup around that dependency. Determine the supported path for using a system-installed Perl instead; done means rules_perl can build on Power architecture without a relocatable_perl Power tarball. The issue has had no recent response.

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