Explicitly namespace OS-specific definitions

[mzabaluev]

There are reexports at the top level that are only available in Unix or Windows:

#[cfg(unix)] pub use consts::os::sysconf::*;

#[cfg(unix)] pub use funcs::posix88::mman::*;
#[cfg(unix)] pub use funcs::posix88::dirent::*;
#[cfg(unix)] pub use funcs::posix88::net::*;
#[cfg(unix)] pub use funcs::posix01::stat_::*;
#[cfg(unix)] pub use funcs::posix01::unistd::*;
#[cfg(unix)] pub use funcs::posix01::resource::*;


#[cfg(windows)] pub use funcs::extra::kernel32::*;
#[cfg(windows)] pub use funcs::extra::winsock::*;
#[cfg(windows)] pub use funcs::extra::msvcrt::*;

For clarity, and following the convention in std, these are better exported for public use in explicitly OS-specific modules os::unix and os::windows, and the top-level reexports deprecated.

[alexcrichton]

Thanks for the report! This repo is actually currently slated for a revamp, as detailed in an RFC: rust-lang/rfcs#1291. The intention is to slate this library as platform-specific by default rather than platform-agnostic by default, but comments on the RFC are always welcome!