diff --git a/headers/compatibility/bsd/vis.h b/headers/compatibility/bsd/vis.h
index cb331b8aae..d9d37281e6 100644
--- a/headers/compatibility/bsd/vis.h
+++ b/headers/compatibility/bsd/vis.h
@@ -35,6 +35,10 @@
 #ifndef _VIS_H_
 #define	_VIS_H_
 
+
+#ifdef _BSD_SOURCE
+
+
 #include <sys/types.h>
 
 /*
@@ -119,4 +123,6 @@ int	unvis(char *, int, int *, int);
 #endif
 __END_DECLS
 
+#endif
+
 #endif /* !_VIS_H_ */