diff --git a/src/lua/fio.cc b/src/lua/fio.cc
index 721c68af8af0c3e8419c31bcdadadddf6a82d4ee..28507687681f398f3c272a02a6619130d19cc12a 100644
--- a/src/lua/fio.cc
+++ b/src/lua/fio.cc
@@ -26,7 +26,6 @@
  * THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  * SUCH DAMAGE.
  */
-#define _POSIX_SOURCE
 #include "lua/fio.h"
 #include <sys/types.h>
 #include <sys/stat.h>