platforms/libc/BUILD.bazel

constraint_setting(
    name = "libc",
    default_constraint_value = "unconstrained",
    visibility = ["//visibility:public"],
)

constraint_value(
    name = "unconstrained",
    constraint_setting = "libc",
    visibility = ["//visibility:public"],
)

constraint_value(
    name = "glibc",
    constraint_setting = "libc",
    visibility = ["//visibility:public"],
)

constraint_value(
    name = "musl",
    constraint_setting = "libc",
    visibility = ["//visibility:public"],
)