Runtime removal: refactor tty

This patch continues runtime removal by moving the tty implementations
into `sys`.

Because this eliminates APIs in `libnative` and `librustrt`, it is a:

[breaking-change]

This functionality is likely to be available publicly, in some form,
from `std` in the future.

1 files changed, 8 insertions, 0 deletions

diff --git a/src/libstd/sys/common/mod.rs b/src/libstd/sys/common/mod.rs
index 75c2987078d..c5f8214a5c3 100644
--- a/src/libstd/sys/common/mod.rs
+++ b/src/libstd/sys/common/mod.rs
@@ -48,6 +48,14 @@ pub fn short_write(n: uint, desc: &'static str) -> IoError {
     }
 }
 
+pub fn unimpl() -> IoError {
+    IoError {
+        kind: io::IoUnavailable,
+        desc: "operations not yet supported",
+        detail: None,
+    }
+}
+
 // unix has nonzero values as errors
 pub fn mkerr_libc<Int: num::Zero>(ret: Int) -> IoResult<()> {
     if !ret.is_zero() {