Cargo Features

grb-sys2 has no features set by default.

[dependencies]
grb-sys2 = { version = "10.1.1", features = ["build_script_tests"] }
build_script_tests = anyhow

Features from optional dependencies

In crates that don't use the dep: syntax, optional dependencies automatically become Cargo features. These features may have been created by mistake, and this functionality may be removed in the future.

anyhow build_script_tests?