Adjust some `#[cfg]`s to take non-Unix non-Windows operating systems into account
Adjust some `#[cfg]`s to take non-Unix non-Windows operating systems into account

aidancully/rust,aidancully/rust,graydon/rust,graydon/rust,aidancully/rust,aidancully/rust,aidancully/rust,aidancully/rust,graydon/rust,graydon/rust,graydon/rust,graydon/rust