Index: src/core/main.c
--- src/core/main.c.orig
+++ src/core/main.c
@@ -42,7 +42,7 @@
  */
 
 #define _GNU_SOURCE
-#define _XOPEN_SOURCE /* for putenv() and some signal-related functions */
+#define _XOPEN_SOURCE 700 /* for putenv() and some signal-related functions */
 
 #include <config.h>
 #include <glib/gi18n-lib.h>
