--- src/ui/theme.c.orig	2015-05-13 18:52:13.340057387 +0200
+++ src/ui/theme.c	2015-05-13 18:55:30.469306867 +0200
@@ -60,7 +60,8 @@
 #include <gtk/gtk.h>
 #include <string.h>
 #include <stdlib.h>
 #define __USE_XOPEN
+#define _XOPEN_SOURCE
 #include <math.h>
 
 #define GDK_COLOR_RGBA(color)                                           \
