Upgrade protobuf to v3.6.1
Merge commit 'be9845eb2abf508c86da76321b4e2c352b45b532' into master
Change-Id: I1b3cd2e177686afe95f44abc4fb0c6f9e001e784
diff --git a/third_party/protobuf/util/python/BUILD b/third_party/protobuf/util/python/BUILD
index 073ea63..8a6dd59 100644
--- a/third_party/protobuf/util/python/BUILD
+++ b/third_party/protobuf/util/python/BUILD
@@ -3,7 +3,17 @@
# This is a placeholder for python headers. Projects needing to use
# fast cpp protos in protobuf's python interface should build with
# --define=use_fast_cpp_protos=true, and in addition, provide
-# //util/python:python_headers dependency that in turn provides Python.h.
+# //external:python_headers dependency that in turn provides Python.h.
+#
+# Projects that include protobuf using a Bazel external repository will need to
+# add a workspace rule to their WORKSPACE files to add an external workspace
+# that includes the Python headers. For example, the protobuf WORKSPACE file
+# includes the following local_repository rule that points to this directory:
+#
+# new_local_repository(
+# name = "python",
+# path = __workspace_dir__ + "/util/python",
+# )
cc_library(
name = "python_headers",
visibility = ["//visibility:public"],