https://bugs.gentoo.org/426254

From 81ae188c8d1b42d187b97846e3b31479a00d4720 Mon Sep 17 00:00:00 2001
From: Takashi Iwai <tiwai@suse.de>
Date: Tue, 31 Jul 2012 11:18:54 +0200
Subject: [PATCH] usb_stream: Fix build with glibc 2.16

_GNU_SOURCE needs to be defined at first.

Signed-off-by: Takashi Iwai <tiwai@suse.de>
---
 usb_stream/pcm_usb_stream.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/usb_stream/pcm_usb_stream.c b/usb_stream/pcm_usb_stream.c
index b1fd68f..8220849 100644
--- a/usb_stream/pcm_usb_stream.c
+++ b/usb_stream/pcm_usb_stream.c
@@ -18,8 +18,8 @@
  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307 USA
  */
 
-#include <byteswap.h>
 #define _GNU_SOURCE
+#include <byteswap.h>
 #include <sys/mman.h>
 #include <sys/shm.h>
 #include <sys/ioctl.h>
-- 
1.7.9.7