Documentation for @bazel_tools//src/conditions

[laurentlb]

@laszlocsomor used this technique in a bzl file to test if we're on Windows:

        is_windows = select({
            "@bazel_tools//src/conditions:host_windows": True,
            "//conditions:default": False,
        }),

I didn't find anything about @bazel_tools//src/conditions in the documentation.

[laszlocsomor]

I used this pattern in bazelbuild/bazel-skylib#123.

[yogurtearl]

Related:

https://bazel.build/docs/configurable-attributes

https://github.com/bazelbuild/bazel/blame/364b77ed34afcd07d48313472e8fe3b260a8312f/src/conditions/BUILD

[aiuto]

Obsolete. We should be removing this in favor of the @platforms repo.