List of labels; optional; nonconfigurable
The set of targets whose Make variables the rule is allowed
to access. These rules are either rules that provide
the TemplateVariableInfo
provider or special targets for toolchain types built into
Bazel.
These include:
@bazel_tools//tools/cpp:current_cc_toolchain
@bazel_tools//tools/cpp:current_java_runtime
Note that this is distinct from the concept of toolchain resolution that is used by rule implementations for platform-dependenct configuration. You cannot use this attribute to determine which specific cc_toolchain or java_toolchain a target will use.