message: Allow specifying additional BUILD files for tf_http_archive
  Allows specifying multiple BUILD files for HTTP archive where it is more natural to have multiple BUILD files. This follows the same structure as system_link_files (e.g., map from file to directory in checked out repo).
diff: @@ -118,6 +118,10 @@ def _tf_http_archive(ctx):
  for internal_src, external_dest in ctx.attr.system_link_files.items():
  ctx.symlink(Label(internal_src), ctx.path(external_dest))
  + if ctx.attr.additional_build_files:
  + for internal_src, external_dest in ctx.attr.additional_build_files.items():
  + ctx.symlink(Label(internal_src), ctx.path(external_dest))
  +
  tf_http_archive = repository_rule(
  implementation = _tf_http_archive,
  attrs = {
  @@ -130,6 +134,7 @@ tf_http_archive = repository_rule(
  "build_file": attr.label(),
  "system_build_file": attr.label(),
  "system_link_files": attr.string_dict(),
  + "additional_build_files": attr.string_dict(),
  },
  environ = [
  "TF_SYSTEM_LIBS",
  