Index: uspace/lib/posix/include/posix/string.h
===================================================================
--- uspace/lib/posix/include/posix/string.h	(revision bd41ac52cf7d20e9e568c519bf2cb5ac7104b86a)
+++ uspace/lib/posix/include/posix/string.h	(revision cca80a20e6e2bf961374aa1b1f10e61420a705de)
@@ -48,6 +48,11 @@
 
 #include "libc/mem.h"
+#ifdef _HELENOS_SOURCE
 #undef _HELENOS_SOURCE
 #include "libc/string.h"
+#define _HELENOS_SOURCE
+#else
+#include "libc/string.h"
+#endif
 
 /* Copying and Concatenation */