bazel_benchmark checks out rules_go to a temporary directory, creates
a temporary workspace, measures the time it takes to build various
targets, then appends the times to a .csv file.

This will probably be much more sophisticated in the future, but it's
good to have something basic now.

bazel_benchmark.sh is now responsible for cloning rules_go at master
into a temp directory. This script can be copied to a bin directory
and run with a timer. The rest of the bazel_benchmark.go logic will
run at the tip of master.

Also: record Bazel version in the output file.

The googleapis repository seems to be of such a size that it takes a
long time to clone on a link with lower bandwidth. So long, in fact,
that it causes timeouts in my case.

…d() (#1602)

…lchain (#1605)

//tools/defaults is a special case which is being removed in Bazel.

go_sdk is a new rule that gathers information about an SDK and returns
a GoSDK provider which will get wired into the toolchain.

package_list is a new rule that generates a list of importable
packages from the sources in the SDK (previously, we invoked go list,
which is slower).

* go_toolchain has a new mandatory attribute, "sdk", which be
  something that provides GoSDK.
* go_host_sdk, go_local_sdk, and go_download_sdk are now macros that
  wrap the old rules. Each rule declares toolchains in its BUILD.bazel
  file that work on the host architecture. The macro calls
  register_toolchains with these.
* go_register_toolchains no longer calls register_toolchains, but it
  will an SDK rule if "go_sdk" isn't defined. This is a step toward
  allowing multiple SDKs to support multiple execution platforms.
* Action inputs are narrowed to use go.sdk.tools and go.stdlib.libs
  rather than larger sets of files.

go_wrap_sdk allows you to configure a Go SDK that was downloaded or
located with another repository rule.

Related #1611

* Use add_all() to lazily construct args

* add_joined() omits the argument if value is an empty list

* Optimize compile

* Optimize cover

* Simplify tags argument construction

* Use any() instead of a dict

* Undo depset() usage

… ci] (#1624)

* Create .bazelrc

See bazelbuild/bazel#5756 (comment)

* Update .bazelrc

attr.label() converts strings into labels by itself.

This will eventually be removed when old versions of Gazelle are no
longer supported and nothing depends on the file by name.

If not provided as an input, go_sdk will generate the file itself.

Also remove allow_files where it conflicts with allow_single_file (not
allowed).
Also remove both allow_files and allow_single_file in private attributes
where executable is set to True (a file cannot be specified anyway -
private attribute).

Fixes #1548

* Propagate mode aspect on "_coverdata" edges

This ensures the coverdata library is built in the same mode as the
binary that depends on it.

Fixes #1630

* set pure = "on" on test to make CI happy

bazel_gazelle to master as of 2018-08-06
com_google_protobuf to v3.6.1
com_github_goog_protobuf to v1.1.1
org_golang_x_net to master as of 2018-08-06
org_golang_google_grpc to v1.14.0
org_golang_google_genproto to master as of 2018-08-06
go_googleapis to master as of 2018-08-06
com_github_kevinburke_go_bindata to v3.11.0
org_golang_x_tools to master as of 2018-08-07

Also, fix gazelle example to use prefix directive instead of
attribute.

* Add CI config to test on RBE.

* Disable BAZEL_DO_NOT_DETECT_CPP_TOOLCHAIN.

This is set by default in the rbe_ubuntu1604 platform, but tests in this
repo need this to be disabled.

* Skip tests that are not RBE compatible.

The newest version of gRPC depends on @org_golang_x_sys. Since we
provide other gRPC dependencies, we should declare this one as well.

Fixes #1648

Related #1649

Multiple param files are now supported as well.

Both helpers enable multiline files. Any action using either of these
helpers should support them. Other actions may use go.actions.args.

go.builder_args adds default arguments that builders should be able to
interpret, including -sdk and -tags.

go.args is deprecated.

The Go toolchain has supported importcfg files since 1.9. These files
give the build system finer control over dependencies using importmap
and packagefile declarations. Using these files allows us to abandon
-I and -L flags, which will help us stay under command line length
limits.

Fixes #1637

* update org_golang_google_genproto

* update go_googleapis

Related #1637

The "data" configuration has been deprecated for a while and has no
effect.

go_rules_dependencies no longer declares the following repositories:

* bazel_gazelle
* com_github_bazelbuild_buildtools
* com_github_pelletier_go_toml

The "gazelle" rule is removed from //go:def.bzl. It has been
deprecated for some time, and "gazelle fix" replaces it.

…ble (#1647)

A test in the old version of org_golang_x_crypto we were testing fails
with Go 1.11. This is fixed in newer versions.

This removes the need for --incompatible_disallow_dict_plus