This change adds the required loads to examples and zlib.
For full compatibility with --incompatible_load_{cc,java,proto}_rules_from_bzl,
we will need to roll gtest to a newer version.

* Fix reference to six in //:protobuf_python rule

* Add six to protobuf_deps.bzl

* Use six archive directly as repo @six

Support for using proto_library in this attribute was added in:
https://github.com/bazelbuild/bazel/commit/a5ee2c4d979441e663cf53b2ace4daa05e5033d8

Legacy support for using .proto files will be removed in a future
version of Bazel.

Otherwise, sandbox and remote execution will complain `google/protobuf/port_def.inc` doesn't exist.

that builds the JavaLite runtime.

Contents based on java/lite/pom.xml.

All bazel crosstools automatically pass -Wall to compiles. The order of
operations is:

- bazel crosstool flags
- `--host_copt` flags and other variations like `--host_cxxopt`
- the `copts` defined on the rule

Because of this when protobuf produces warnings, there's no way to
disable them from the consumer side if they are re-enabled later by
another `-Wall` flag.

Recently dependency to error_prone_annotations was added to the code,
but only Maven build tool chain was updated.

Closes #5795.

Recently dependency to error_prone_annotations was added to the code,
but only Maven build tool chain was updated.

Closes #5795.

* Down-integrate internal changes to github.

* Fix BUILD file and regenerate csharp descritpor

The -Wno-writable-strings warning flag is Clang-specific. GCC's
equivalent is -Wno-write-strings, which Clang also supports as a
synonym. So, -Wno-write strings is more compatible and there is no need
to specify both.

https://clang.llvm.org/docs/DiagnosticsReference.html#wwrite-strings
https://gcc.gnu.org/onlinedocs/gcc/Warning-Options.html

* Add Bazel config for optional zlib support

* Add hard dependency on zlib

* Remove unused config_setting

* Add Bazel config for optional zlib support

* Add hard dependency on zlib

* Remove unused config_setting

Not sure the history for why there were two objc_library targets, but
given the one has an issue about not working, merge them into a single
target and an alias.

- Use the alias for :objectivec since that naming doesn't seem to follow
  the other targets *_library targets here.
- Update :protobuf_objc to be use for the working target and just inline
  the sources/headers lists so there is less indirection in the file.

Fixes #5284

Fixes https://github.com/google/protobuf/issues/3957

* Fixes https://github.com/google/protobuf/issues/5031
* Fixes https://github.com/google/protobuf/issues/5037

* Delete unused files.

* Remove js_embed binary.