diff --git a/test cases/frameworks/1 boost/linkexe.cc b/test cases/frameworks/1 boost/linkexe.cc
index 240c7c1ec..e00edee19 100644
--- a/test cases/frameworks/1 boost/linkexe.cc	
+++ b/test cases/frameworks/1 boost/linkexe.cc	
@@ -1,3 +1,5 @@
+#define _XOPEN_SOURCE 500
+
 #include<boost/thread.hpp>
 
 boost::recursive_mutex m;