Upgrade to nix version 0.7

Cargo.toml

@@ -14,7 +14,7 @@ libc = "0.2.7"
 unicode-width = "0.1.3"
 
 [target.'cfg(unix)'.dependencies]
-nix = "0.5.0"
+nix = "0.7"
 
 [target.'cfg(windows)'.dependencies]
 winapi = "0.2"

src/tty/unix.rs

@@ -228,13 +228,13 @@ static SIGWINCH: atomic::AtomicBool = atomic::ATOMIC_BOOL_INIT;
 fn install_sigwinch_handler() {
     SIGWINCH_ONCE.call_once(|| unsafe {
         let sigwinch = signal::SigAction::new(signal::SigHandler::Handler(sigwinch_handler),
-                                              signal::SaFlag::empty(),
+                                              signal::SaFlags::empty(),
                                               signal::SigSet::empty());
         let _ = signal::sigaction(signal::SIGWINCH, &sigwinch);
     });
 }
 
-extern "C" fn sigwinch_handler(_: signal::SigNum) {
+extern "C" fn sigwinch_handler(_: libc::c_int) {
     SIGWINCH.store(true, atomic::Ordering::SeqCst);
 }