rustc: Disable fragile tcp tests on Darwin

This is an alternative implementation of
https://github.com/NixOS/nixpkgs/pull/21741/files

pkgs/development/compilers/rust/default.nix

@@ -4,7 +4,6 @@
 let
   rustPlatform = recurseIntoAttrs (makeRustPlatform (callPackage ./bootstrap.nix {}));
 in
-
 rec {
   rustc = callPackage ./rustc.nix {
     shortVersion = "1.14";
@@ -16,6 +15,7 @@ rec {
 
     patches = [
       ./patches/disable-lockfile-check-stable.patch
+      ./patches/darwin-disable-fragile-tcp-tests.patch
     ] ++ stdenv.lib.optional stdenv.needsPax ./patches/grsec.patch;
 
     inherit targets;

pkgs/development/compilers/rust/patches/darwin-disable-fragile-tcp-tests.patch

@@ -0,0 +1,36 @@
+From 0becb0b7cff0176279fc9f94c91299d788a43941 Mon Sep 17 00:00:00 2001
+From: Moritz Ulrich <moritz@tarn-vedra.de>
+Date: Sun, 8 Jan 2017 10:28:17 +0100
+Subject: [PATCH] Disable libstd::net::tcp::{ttl, timeouts} on Darwin
+
+---
+ src/libstd/net/tcp.rs | 6 +++++-
+ 1 file changed, 5 insertions(+), 1 deletion(-)
+
+diff --git a/src/libstd/net/tcp.rs b/src/libstd/net/tcp.rs
+index 0e7c5b0671..189c31b958 100644
+--- a/src/libstd/net/tcp.rs
++++ b/src/libstd/net/tcp.rs
+@@ -1022,7 +1022,10 @@ mod tests {
+
+     // FIXME: re-enabled bitrig/openbsd tests once their socket timeout code
+     //        no longer has rounding errors.
+-    #[cfg_attr(any(target_os = "bitrig", target_os = "netbsd", target_os = "openbsd"), ignore)]
++  #[cfg_attr(any(target_os = "bitrig",
++                 target_os = "netbsd",
++                 target_os = "openbsd",
++                 target_os = "macos"), ignore)]
+     #[test]
+     fn timeouts() {
+         let addr = next_test_ip4();
+@@ -1101,6 +1104,7 @@ mod tests {
+         assert_eq!(false, t!(stream.nodelay()));
+     }
+
++    #[cfg_attr(target_os = "macos", ignore)]
+     #[test]
+     fn ttl() {
+         let ttl = 100;
+-- 
+2.11.0
+