Including unsafe Rust Code
Unsafe Rust code is forbidden in rust_static_library by default — it won’t
compile. If you need unsafe Rust code, add allow_unsafe = true to the gn
target. (Later in the course we’ll see circumstances where this is necessary.)
import("//build/rust/rust_static_library.gni")
rust_static_library("my_rust_lib") {
  crate_root = "lib.rs"
  sources = [
    "lib.rs",
    "hippopotamus.rs"
  ]
  allow_unsafe = true
}