warning: unexpected `cfg` condition name: `has_foo`
  --> $DIR/cargo-build-script.rs:10:7
   |
LL | #[cfg(has_foo)]
   |       ^^^^^^^
   |
   = help: expected names are: `clippy`, `debug_assertions`, `doc`, `doctest`, `fmt_debug`, `has_bar`, `miri`, `overflow_checks`, `panic`, `proc_macro`, `relocation_model`, `rustfmt`, `sanitize`, `sanitizer_cfi_generalize_pointers`, `sanitizer_cfi_normalize_integers`, `target_abi`, `target_arch`, `target_endian`, `target_env`, `target_family`, `target_feature`, `target_has_atomic`, `target_has_atomic_equal_alignment`, `target_has_atomic_load_store`, `target_os`, `target_pointer_width`, `target_thread_local`, `target_vendor`, `test`, `ub_checks`, `unix`, and `windows`
   = help: consider using a Cargo feature instead
   = help: or consider adding in `Cargo.toml` the `check-cfg` lint config for the lint:
            [lints.rust]
            unexpected_cfgs = { level = "warn", check-cfg = ['cfg(has_foo)'] }
   = note: see <https://doc.rust-lang.org/nightly/rustc/check-cfg/cargo-specifics.html> for more information about checking conditional configuration
   = note: `#[warn(unexpected_cfgs)]` on by default

warning: unexpected `cfg` condition name: `has_foo`
  --> $DIR/cargo-build-script.rs:14:7
   |
LL | #[cfg(has_foo = "yes")]
   |       ^^^^^^^^^^^^^^^
   |
   = help: consider using a Cargo feature instead
   = help: or consider adding in `Cargo.toml` the `check-cfg` lint config for the lint:
            [lints.rust]
            unexpected_cfgs = { level = "warn", check-cfg = ['cfg(has_foo, values("yes"))'] }
   = note: see <https://doc.rust-lang.org/nightly/rustc/check-cfg/cargo-specifics.html> for more information about checking conditional configuration

warning: unexpected `cfg` condition value: `yes`
  --> $DIR/cargo-build-script.rs:18:7
   |
LL | #[cfg(has_bar = "yes")]
   |       ^^^^^^^--------
   |              |
   |              help: remove the value
   |
   = note: no expected value for `has_bar`
   = help: consider using a Cargo feature instead
   = help: or consider adding in `Cargo.toml` the `check-cfg` lint config for the lint:
            [lints.rust]
            unexpected_cfgs = { level = "warn", check-cfg = ['cfg(has_bar, values("yes"))'] }
   = note: see <https://doc.rust-lang.org/nightly/rustc/check-cfg/cargo-specifics.html> for more information about checking conditional configuration

warning: 3 warnings emitted