diff --git a/src/CMakeLists.txt b/src/CMakeLists.txt
--- a/src/CMakeLists.txt
+++ b/src/CMakeLists.txt
@@ -9,7 +9,7 @@
 
 # C-Definitions
 ADD_DEFINITIONS(-Wall -O2 -ansi)
-ADD_DEFINITIONS(-D_XOPEN_SOURCE=500)
+ADD_DEFINITIONS(-D_XOPEN_SOURCE=600)
 ADD_DEFINITIONS(-DBOT_VERSION=0.99)
 
 # Includes