Import bazelbuild/platforms from GitHub.

- e51978ee25 initial checkin by Tony Aiuto <aiuto@google.com>
  - d91995f1a9 Add CONTRIBUTING.md by Tony Aiuto <aiuto@google.com>

GIT_ORIGIN_REV_ID=d91995f1a9497602a02d11db41a7ffa5551147be

RELNOTES: None.
PiperOrigin-RevId: 251811887
Change-Id: Iadfdbbc9d013343e495067ebf51b1e0ea59e0fe6

CODEOWNERS

@@ -0,0 +1 @@
+@aiuto @aragos @gregestren @katre

CONTRIBUTING.md

@@ -1,12 +1,9 @@
-# How to Contribute
-
-We'd love to accept your patches and contributions to this project. There are
-just a few small guidelines you need to follow.
+# Contributing to Bazel
 
 ## Contributor License Agreement
 
 Contributions to this project must be accompanied by a Contributor License
-Agreement. You (or your employer) retain the copyright to your contribution;
+Agreement. You (or your employer) retain the copyright to your contribution,
 this simply gives us permission to use and redistribute your contributions as
 part of the project. Head over to <https://cla.developers.google.com/> to see
 your current agreements on file or to sign a new one.
@@ -15,14 +12,13 @@ You generally only need to submit a CLA once, so if you've already submitted one
 (even if it was for a different project), you probably don't need to do it
 again.
 
-## Code reviews
+## Patch Acceptance Process
 
-All submissions, including submissions by project members, require review. We
-use GitHub pull requests for this purpose. Consult
-[GitHub Help](https://help.github.com/articles/about-pull-requests/) for more
-information on using pull requests.
+The process is described in the [README for this repository](README.md). For
+background, you should also understand how to
+[contribute to Bazel](https://bazel.build/contributing.html).
 
-## Community Guidelines
+## Setting up your development environment
 
-This project follows
-[Google's Open Source Community Guidelines](https://opensource.google.com/conduct/).
+Read how to
+[set up your development environment](https://bazel.build/contributing.html).

WORKSPACE

@@ -0,0 +1 @@
+workspace(name = "platforms")

cpu/BUILD

@@ -0,0 +1,44 @@
+# Standard cpu name constraint_setting and constraint_values
+licenses(["notice"])
+
+package(
+    default_visibility = ["//visibility:public"],
+)
+
+filegroup(
+    name = "srcs",
+    srcs = glob(["**"]),
+)
+
+# These match values in https://github.com/bazelbuild/bazel/blob/master/src/main/java/com/google/devtools/build/lib/util/CPU.java
+constraint_setting(name = "cpu")
+
+constraint_value(
+    name = "x86_32",
+    constraint_setting = ":cpu",
+)
+
+constraint_value(
+    name = "x86_64",
+    constraint_setting = ":cpu",
+)
+
+constraint_value(
+    name = "ppc",
+    constraint_setting = ":cpu",
+)
+
+constraint_value(
+    name = "arm",
+    constraint_setting = ":cpu",
+)
+
+constraint_value(
+    name = "aarch64",
+    constraint_setting = ":cpu",
+)
+
+constraint_value(
+    name = "s390x",
+    constraint_setting = ":cpu",
+)

os/BUILD

@@ -0,0 +1,44 @@
+# Standard constraint_setting and constraint_values to be used in platforms.
+licenses(["notice"])
+
+package(
+    default_visibility = ["//visibility:public"],
+)
+
+filegroup(
+    name = "srcs",
+    srcs = glob(["**"]),
+)
+
+# These match values in https://github.com/bazelbuild/bazel/blob/master/src/main/java/com/google/devtools/build/lib/util/OS.java
+constraint_setting(name = "os")
+
+constraint_value(
+    name = "osx",
+    constraint_setting = ":os",
+)
+
+constraint_value(
+    name = "ios",
+    constraint_setting = ":os",
+)
+
+constraint_value(
+    name = "freebsd",
+    constraint_setting = ":os",
+)
+
+constraint_value(
+    name = "android",
+    constraint_setting = ":os",
+)
+
+constraint_value(
+    name = "linux",
+    constraint_setting = ":os",
+)
+
+constraint_value(
+    name = "windows",
+    constraint_setting = ":os",
+)