Add run_make_support::build_native_static_lib function

Author: GuillaumeGomez

src/tools/run-make-support/src/lib.rs

@@ -55,7 +55,21 @@ pub use python::python_command;
 pub use rustc::{aux_build, bare_rustc, rustc, Rustc};
 pub use rustdoc::{bare_rustdoc, rustdoc, Rustdoc};
 
-/// [`diff`][mod@diff] is implemented in terms of the [similar] library.
+/// Implement common helpers for command wrappers. This assumes that the command wrapper is a struct
+/// containing a `cmd: Command` field and a `output` function. The provided helpers are:
+///
+/// 1. Generic argument acceptors: `arg` and `args` (delegated to [`Command`]). These are intended
+///    to be *fallback* argument acceptors, when specific helpers don't make sense. Prefer to add
+///    new specific helper methods over relying on these generic argument providers.
+/// 2. Environment manipulation methods: `env`, `env_remove` and `env_clear`: these delegate to
+///    methods of the same name on [`Command`].
+/// 3. Output and execution: `output`, `run` and `run_fail` are provided. `output` waits for the
+///    command to finish running and returns the process's [`Output`]. `run` and `run_fail` are
+///    higher-level convenience methods which waits for the command to finish running and assert
+///    that the command successfully ran or failed as expected. Prefer `run` and `run_fail` when
+///    possible.
+///
+/// Example usage:
 ///
 /// [similar]: https://github.com/mitsuhiko/similar
 pub use diff::{diff, Diff};