From 2ffc96616b53c488417b044f320ab0d91e4942e9 Mon Sep 17 00:00:00 2001
From: David Cuddeback <david.cuddeback@gmail.com>
Date: Sun, 19 Nov 2017 17:57:09 -0700
Subject: [PATCH] Fix errno location on DragonFly BSD

DragonFlyBSD uses a thread-local variable for errno. libstd uses a
feature (`thread_local`) which is not stablized [1].

[1] https://github.com/rust-lang/rust/issues/29594
---
 serial-unix/Cargo.toml   |  3 +++
 serial-unix/src/error.rs | 14 +++-----------
 serial-unix/src/lib.rs   |  3 +++
 3 files changed, 9 insertions(+), 11 deletions(-)

diff --git a/serial-unix/Cargo.toml b/serial-unix/Cargo.toml
index 05514e1..62f5635 100644
--- a/serial-unix/Cargo.toml
+++ b/serial-unix/Cargo.toml
@@ -14,3 +14,6 @@ categories = ["hardware-support", "os", "os::unix-apis"]
 [dependencies]
 serial-core = { version = "0.4", path = "../serial-core" }
 libc = "0.2.33"
+
+[target.'cfg(target_os="dragonfly")'.dependencies]
+errno-dragonfly = "0.1.1"
diff --git a/serial-unix/src/error.rs b/serial-unix/src/error.rs
index 8cebb56..4a32d9a 100644
--- a/serial-unix/src/error.rs
+++ b/serial-unix/src/error.rs
@@ -28,6 +28,9 @@ use std::str;
 
 use libc::{c_int, c_char};
 
+#[cfg(target_os = "dragonfly")]
+use dfly::errno_location;
+
 pub fn last_os_error() -> core::Error {
     from_raw_os_error(errno())
 }
@@ -73,23 +76,12 @@ extern {
     fn errno_location() -> *mut c_int;
 }
 
-#[cfg(not(target_os = "dragonfly"))]
 pub fn errno() -> i32 {
     unsafe {
         (*errno_location()) as i32
     }
 }
 
-#[cfg(target_os = "dragonfly")]
-pub fn errno() -> i32 {
-    extern {
-        #[thread_local]
-        static errno: c_int;
-    }
-
-    unsafe { errno as i32 }
-}
-
 pub fn error_string(errno: i32) -> String {
     extern {
         #[cfg_attr(any(target_os = "linux", target_env = "newlib"),
diff --git a/serial-unix/src/lib.rs b/serial-unix/src/lib.rs
index 0bbbace..837b0b0 100644
--- a/serial-unix/src/lib.rs
+++ b/serial-unix/src/lib.rs
@@ -24,6 +24,9 @@
 extern crate serial_core as core;
 extern crate libc;
 
+#[cfg(target_os = "dragonfly")]
+extern crate errno_dragonfly as dfly;
+
 pub use tty::*;
 
 mod error;