From 33fad0e636d7b43a9d37595ce045318c67457e7a Mon Sep 17 00:00:00 2001
From: "Ryan C. Gordon" <icculus@icculus.org>
Date: Mon, 23 Mar 2015 20:10:08 -0400
Subject: [PATCH] SDL-1.2: Fixed recursive mutexes on Linux (thanks, Ozkan!).

---
 configure.in                      | 6 ++++--
 src/thread/pthread/SDL_sysmutex.c | 3 +++
 2 files changed, 7 insertions(+), 2 deletions(-)

diff --git a/configure.in b/configure.in
index dfae09947..b75fae20f 100644
--- a/configure.in
+++ b/configure.in
@@ -2022,7 +2022,8 @@ AC_HELP_STRING([--enable-pthread-sem], [use pthread semaphores [[default=yes]]])
             AC_MSG_CHECKING(for recursive mutexes)
             has_recursive_mutexes=no
             if test x$has_recursive_mutexes = xno; then
-                AC_TRY_COMPILE([
+                AC_TRY_LINK([
+                  #define _GNU_SOURCE 1
                   #include <pthread.h>
                 ],[
                   pthread_mutexattr_t attr;
@@ -2033,7 +2034,8 @@ AC_HELP_STRING([--enable-pthread-sem], [use pthread semaphores [[default=yes]]])
                 ])
             fi
             if test x$has_recursive_mutexes = xno; then
-                AC_TRY_COMPILE([
+                AC_TRY_LINK([
+                  #define _GNU_SOURCE 1
                   #include <pthread.h>
                 ],[
                   pthread_mutexattr_t attr;
diff --git a/src/thread/pthread/SDL_sysmutex.c b/src/thread/pthread/SDL_sysmutex.c
index c3b8ce2c3..4b3063831 100644
--- a/src/thread/pthread/SDL_sysmutex.c
+++ b/src/thread/pthread/SDL_sysmutex.c
@@ -21,6 +21,9 @@
 */
 #include "SDL_config.h"
 
+#ifndef _GNU_SOURCE
+#define _GNU_SOURCE
+#endif
 #include <pthread.h>
 
 #include "SDL_thread.h"