Remove or revamp sys::syscall module #341
Description
This came up in a comment from @pnkfelix on #339.
This module appears to be Linux specific. It declares
extern {
pub fn syscall(num: Syscall, ...) -> c_int;
}for all architectures, with Syscall being architecture dependent alias that is c_long on all listed architectures.
On Linux, [syscall(2)][syscall] should return a long, so this declaration is incorrect. We should switch to using definitions from libc and tidy up or remove this module.
Related: #264