Set _GNU_SOURCE in config.mk

abduco.c

@@ -13,7 +13,6 @@
  * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
  * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
  */
-#define _GNU_SOURCE
 #include <errno.h>
 #include <fcntl.h>
 #include <stdio.h>

config.mk

@@ -15,7 +15,7 @@ LIBS = -lc -lutil
 # Solaris
 #LIBS = -lc -lsocket
 
-CFLAGS += -std=c99 -Os ${INCS} -DVERSION=\"${VERSION}\" -DNDEBUG
+CFLAGS += -std=c99 -Os ${INCS} -DVERSION=\"${VERSION}\" -DNDEBUG -D_GNU_SOURCE
 LDFLAGS += ${LIBS}
 
 DEBUG_CFLAGS = ${CFLAGS} -UNDEBUG -O0 -g -ggdb -Wall