Just removing some unnecessary imports.

add time, localtime

time, localtime and strftime are all in POSIX.1 and should IMO all be part of `libc`.

I [tested the bindings](https://github.com/philippkeller/apue-rust/blob/master/src/bin/f06-11-strftime.rs) - works fine on OSX and linux.

And: I added the netbsd aliases based on `time.h` of netbsd

Fix lifetimes with raw identifiers.

Bumps [rand_os](https://github.com/rust-random/rand) from 0.1.2 to 0.1.3.
- [Release notes](https://github.com/rust-random/rand/releases)
- [Changelog](https://github.com/rust-random/rand/blob/master/CHANGELOG.md)
- [Commits](rust-random/rand@rand_os-0.1.2...rand_os-0.1.3)

Signed-off-by: dependabot[bot] <support@dependabot.com>

* Combine integration tests in one test suite

* Combine unit tests in one test suite

Add arm64ec support

Add support to Ubuntu 18.04 (rust-lang#393)

Issue: Our python scripts use python 3.8+ while ubuntu 18.04 defaults
       to python 3.6.

Changes:
 * Change our scripts to use constructs available in older python versions.
 * Modify workflows file to add ubuntu-18.04.
 * Make ubuntu scripts generic.
 * Change copyright check script to ignore directories and symbolic links to directories.