diff --git a/src/Makefile.am b/src/Makefile.am
index 64017425f..615a18529 100644
--- a/src/Makefile.am
+++ b/src/Makefile.am
@@ -1,5 +1,5 @@
 AM_CPPFLAGS = @GLIB_CFLAGS@ -DPACKAGE_DATA_DIR=\"$(pkgdatadir)\" @PYTHON_INCLUDE@
-AM_CFLAGS = @AM_CFLAGS@ @PTHREAD_CFLAGS@ @HAMLIB_CFLAGS@ @CURSES_CFLAGS@
+AM_CFLAGS = @AM_CFLAGS@ @PTHREAD_CFLAGS@ @HAMLIB_CFLAGS@ @CURSES_CFLAGS@ -D_GNU_SOURCE
 
 bin_PROGRAMS = tlf
 
diff --git a/src/addcall.c b/src/addcall.c
index d5adfd026..6f00c742c 100644
--- a/src/addcall.c
+++ b/src/addcall.c
@@ -23,13 +23,6 @@
  *      add call/band to dupe list
  *
  *--------------------------------------------------------------*/
-#ifndef _GNU_SOURCE
-#define _GNU_SOURCE
-#endif
-
-#ifndef _XOPEN_SOURCE
-#define _XOPEN_SOURCE
-#endif
 
 #include <stdlib.h>
 #include <string.h>
diff --git a/src/cabrillo_utils.c b/src/cabrillo_utils.c
index ed127165e..3af333521 100644
--- a/src/cabrillo_utils.c
+++ b/src/cabrillo_utils.c
@@ -24,10 +24,6 @@
  *--------------------------------------------------------------*/
 
 
-#ifndef _GNU_SOURCE
-#define _GNU_SOURCE
-#endif
-
 #include <stdlib.h>
 #include <string.h>
 #include <unistd.h>
diff --git a/src/get_time.c b/src/get_time.c
index 848ab23f3..247082e73 100644
--- a/src/get_time.c
+++ b/src/get_time.c
@@ -25,9 +25,6 @@
 *  All functions operate on UTC dates/times.
 ---------------------------------------------------------------------------*/
 
-#ifndef _XOPEN_SOURCE
-#define _XOPEN_SOURCE
-#endif
 #include <time.h>
 #include <string.h>
 
diff --git a/src/log_utils.c b/src/log_utils.c
index af5b008cd..301addfe1 100644
--- a/src/log_utils.c
+++ b/src/log_utils.c
@@ -21,10 +21,6 @@
 *
 ---------------------------------------------------------------------------*/
 
-#ifndef _GNU_SOURCE
-#define _GNU_SOURCE
-#endif
-
 #include <ctype.h>
 #include <glib.h>
 #include <stdlib.h>
diff --git a/src/readcabrillo.c b/src/readcabrillo.c
index 2c603de4d..d1924c0ac 100644
--- a/src/readcabrillo.c
+++ b/src/readcabrillo.c
@@ -17,9 +17,6 @@
  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301 USA
  */
 
-#ifndef _XOPEN_SOURCE
-#define _XOPEN_SOURCE
-#endif
 #include <stdio.h>
 #include <string.h>
 #include <unistd.h>
diff --git a/src/readcalls.c b/src/readcalls.c
index f953a8eb6..c3722220d 100644
--- a/src/readcalls.c
+++ b/src/readcalls.c
@@ -23,9 +23,6 @@
  *
  *--------------------------------------------------------------*/
 
-#ifndef _XOPEN_SOURCE
-#define _XOPEN_SOURCE
-#endif
 
 #include <stdio.h>
 #include <stdlib.h>
diff --git a/src/rules.c b/src/rules.c
index 84df98679..55f44ef9c 100644
--- a/src/rules.c
+++ b/src/rules.c
@@ -19,10 +19,6 @@
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301 USA
 */
 
-#ifndef _GNU_SOURCE
-#define _GNU_SOURCE	// For asprintf()
-#endif
-
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
diff --git a/src/searchlog.c b/src/searchlog.c
index c0be4657a..8e87320f6 100644
--- a/src/searchlog.c
+++ b/src/searchlog.c
@@ -23,11 +23,6 @@
  *
  *--------------------------------------------------------------*/
 
-#ifndef _GNU_SOURCE
-#define _GNU_SOURCE
-#endif
-
-
 #include <stdbool.h>
 #include <stdlib.h>
 #include <string.h>
diff --git a/src/writecabrillo.c b/src/writecabrillo.c
index b3d4c0586..35b49c640 100644
--- a/src/writecabrillo.c
+++ b/src/writecabrillo.c
@@ -23,10 +23,6 @@
  *--------------------------------------------------------------*/
 
 
-#ifndef _GNU_SOURCE
-#define _GNU_SOURCE
-#endif
-
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>