1 files changed, 1 insertions, 0 deletions
diff --git a/src/feh.h b/src/feh.h
index a4a0a7b..da08aba 100644
--- a/src/feh.h
+++ b/src/feh.h
@@ -27,6 +27,7 @@ CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
 #ifndef FEH_H
 #define FEH_H
 
+#define _GNU_SOURCE
 #include <X11/Xlib.h>
 #include <X11/Xutil.h>
 #include <X11/Xatom.h>