diff --git a/src/buttons.c b/src/buttons.c
index 21245ae6..c55648f5 100644
--- a/src/buttons.c
+++ b/src/buttons.c
@@ -28,12 +28,6 @@
     #include <windows.h>
 #endif
 
-// On Debian, this is already implied in dirent.h
-// I don't know which targets need it and what it does. - yr
-#ifndef _XOPEN_SOURCE
-#define _XOPEN_SOURCE 500
-#endif
-
 #include <fcntl.h>
 #include <stdio.h>
 #include <string.h>
diff --git a/src/mountlist.c b/src/mountlist.c
index e0bc1cb2..3c064507 100644
--- a/src/mountlist.c
+++ b/src/mountlist.c
@@ -47,9 +47,6 @@
     #define MOUNTED_GETMNTENT1
 #endif
 
-#ifndef _XOPEN_SOURCE
-#define _XOPEN_SOURCE 500
-#endif
 // --- END GRAFX2 CUSTOM CONFIG ---
 
 #include "mountlist.h"
diff --git a/src/readini.c b/src/readini.c
index 440f2bbc..3d8b96b8 100644
--- a/src/readini.c
+++ b/src/readini.c
@@ -21,10 +21,6 @@
     You should have received a copy of the GNU General Public License
     along with Grafx2; if not, see <http://www.gnu.org/licenses/>
 */
-#ifndef _XOPEN_SOURCE
-  #define _XOPEN_SOURCE 500
-#endif
-
 #include <stdio.h>
 #include <string.h>
 #include <stdlib.h>
diff --git a/src/realpath.c b/src/realpath.c
index 5a067a4c..bcba03a7 100644
--- a/src/realpath.c
+++ b/src/realpath.c
@@ -1,9 +1,5 @@
 /* vim:expandtab:ts=2 sw=2:
 */
-#ifndef _XOPEN_SOURCE
-#define _XOPEN_SOURCE 500
-#endif
-
 #include <stdlib.h>
 #include <errno.h>
 #include <fcntl.h>