Use rules_pods as a source dependency

I tried to use `git_repository` with `rules_pods` to have the latest fixes from the master branch but it looks like Bazel always looked for the pre-compiled `Compiler` and `RepoTools` under the `bin` directory, which only exists in a release tarball. The current workaround is to do a manual build of `rules_pods` and upload the release tarball somewhere.

Is the any way to use this as a host dependency of `new_pod_repository` so that Bazel will build `rules_pods` first and then use the build results as the build tools for the `new_pod_repository` targets?