Expose defs.bzl form resolved_interpreter_os_alias as a target (#659)

Co-authored-by: Alex Eagle <[email protected]>

Author: UebelAndre

python/private/toolchains_repo.bzl

@@ -87,6 +87,7 @@ def _resolved_interpreter_os_alias_impl(rctx):
     build_contents = """\
 # Generated by python/repositories.bzl
 package(default_visibility = ["//visibility:public"])
+exports_files(["defs.bzl"])
 alias(name = "files",           actual = "@{py_repository}_{host_platform}//:files")
 alias(name = "py3_runtime",     actual = "@{py_repository}_{host_platform}//:py3_runtime")
 alias(name = "python_runtimes", actual = "@{py_repository}_{host_platform}//:python_runtimes")