This commits blanket marks the API of the `std::process` module as `#[stable]`.
The module's API is very similar to the old `std::old_io::process` API and has
generally had quite a bit of time to bake both before and after the new module
landed.
The one modification made to the API is that `Stdio::capture` is now named
`stdio::piped`.
[breaking-change]
The test "signal_reported_right" send a signal `1` to `/bin/sh`, and check
the status code to check if the signal is reported right.
Under OpenBSD, the signal `1` (`SIGHUP`) is catched by `/bin/sh`,
resulting the test failed.
Use the uncatchable signal `9` (`SIGKILL`) for test.
Per [RFC 579](https://github.com/rust-lang/rfcs/pull/579), this commit
adds a new `std::process` module. This module is largely based on the
existing `std::old_io::process` module, but refactors the API to use
`OsStr` and other new standards set out by IO reform.
The existing module is not yet deprecated, to allow for the new API to
get a bit of testing before a mass migration to it.
