diff --git a/hddtemp/src/backtrace.c b/hddtemp/src/backtrace.c

index 878bb37..a205b1a 100644

--- a/hddtemp/src/backtrace.c

+++ b/hddtemp/src/backtrace.c

@@ -16,6 +16,7 @@

  * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA

  */

+#define _GNU_SOURCE

 #include <features.h>

 #if defined(__i386__) && defined(__GLIBC__)

@@ -31,7 +32,7 @@

 #include <bits/sigcontext.h>

 #include <sys/param.h>

-#define __USE_GNU

+//#define __USE_GNU

 #include <ucontext.h>

 #define MAX_BTSIZE 64