Update windows bindings and use windows-targets

[ChrisDenton]

This synchronizes the API definitions with std. Trouble is, std uses its own definition of the windows_targets::link! macro so I've used a path hack to include it in this crate when used as a dependency of std. Otherwise the windows-targets crate is used.

Not sure if this will work but let's see what CI says.

[ChrisDenton]

Oh, path hacks might not work because it looks like there's a difference between fake-std and real-std.

[ChrisDenton]

Hmm... maybe I could make windows_targets crate in std's sysroot and share it that way.

[ChrisDenton]

Ok, with the std changes this should be ready for review now so removing the draft thingy

[workingjubilee]

merge conflicts

[workingjubilee]

Remember that libstd does this for backtrace-rs which allows adding hackery for libstd:

    println!("cargo:rustc-cfg=backtrace_in_libstd");