diff --git a/unix/uxpty.c b/unix/uxpty.c
index 37a017d3..8c25f932 100644
--- a/unix/uxpty.c
+++ b/unix/uxpty.c
@@ -2,8 +2,6 @@
  * Pseudo-tty backend for pterm.
  */
 
-#define _XOPEN_SOURCE 600
-#define _XOPEN_SOURCE_EXTENDED
 #define _GNU_SOURCE
 
 #include <stdio.h>