pidwait: optimize & cross-platform

[FurryR]

Resolves #399 (partially).

Needs to be reviewed before merge as it contains untested code. However it seems that at least the implementation for Linux works fine.

[Krysztal112233]

Thank you for your contribution, I will start reviewing soon :)

[cakebaker]

Hm, at least on my machine (using Linux) your changes make the test test_non_matching_pattern fail as it runs into a timeout:

failures:

---- test_pidwait::test_non_matching_pattern stdout ----
bin: "/home/dho/projects/procps/target/debug/procps"
run: /home/dho/projects/procps/target/debug/procps pidwait THIS_PATTERN_DOES_NOT_MATCH
bin: "/home/dho/projects/procps/target/debug/procps"
run: /home/dho/projects/procps/target/debug/procps pidwait DOES_NOT_MATCH

thread 'test_pidwait::test_non_matching_pattern' panicked at /home/dho/.cargo/registry/src/index.crates.io-1949cf8c6b5b557f/uutests-0.0.30/src/lib/util.rs:1912:35:
called `Result::unwrap()` on an `Err` value: Custom { kind: Other, error: "wait: Timeout of '30s' reached" }
note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace

[cakebaker]

I think you can use workspace = true as this dependency is defined as a workspace dependency in the root Cargo.toml.

Suggested change

	windows-sys = { version = "0.59", features = ["Win32_Foundation", "Win32_System_Threading"] }
	windows-sys = { workspace = true, features = ["Win32_Foundation", "Win32_System_Threading"] }