From de2a9b45e7b4a89affa3ac6d0a010cc627ab4a87 Mon Sep 17 00:00:00 2001
From: "Gary V. Vaughan" <gary@vaughan.pe>
Date: Mon, 6 Apr 2015 18:39:46 -0700
Subject: [PATCH 1/1] sched: workaround glibc _POSIX_PRIORITY_SCHEDULING bug.
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Close #223.
* configure.ac (AC_CHECK_HEADERS): Add sched.h.
* ext/posix/sched.c: Remove unistd.h; Predicate use of priority
scheduling APIs on presence of sched.h instead of
_POSIX_PRIORITY_SCHEDULING macro erroneously defined by glibc on
Linux.
Reported by ncopa@github.com.

Backported from: 11cc8a2973569ec7fb1e7c2466dca0282944b124

Signed-off-by: Gary V. Vaughan <gary@vaughan.pe>
[Backport]
Signed-off-by: Jörg Krause <joerg.krause@embedded.rocks>
---
 configure.ac      | 2 +-
 ext/posix/sched.c | 5 +++--
 2 files changed, 4 insertions(+), 3 deletions(-)

diff --git a/configure.ac b/configure.ac
index aa18318..89a2feb 100644
--- a/configure.ac
+++ b/configure.ac
@@ -114,7 +114,7 @@ gl_INIT
 
 ## Check for header files
 AC_HEADER_STDC
-AC_CHECK_HEADERS([crypt.h strings.h sys/statvfs.h])
+AC_CHECK_HEADERS([crypt.h sched.h strings.h sys/statvfs.h])
 AC_CHECK_HEADERS([net/if.h linux/netlink.h], [], [], [
 #include <sys/socket.h>
 ])
diff --git a/ext/posix/sched.c b/ext/posix/sched.c
index 13b196b..f338d73 100644
--- a/ext/posix/sched.c
+++ b/ext/posix/sched.c
@@ -21,9 +21,10 @@
 
 #include <config.h>
 
-#include <unistd.h>	/* for _POSIX_PRIORITY_SCHEDULING */
+/* cannot use unistd.h for _POSIX_PRIORITY_SCHEDULING, because on Linux
+   glibc it is defined even though the APIs are not implemented :-(     */
 
-#ifdef _POSIX_PRIORITY_SCHEDULING
+#ifdef HAVE_SCHED_H
 #include <sched.h>
 #endif
 
-- 
2.5.2