add posix declaration to buf tests

diff --git a/tests/lib/buf.c b/tests/lib/buf.c
index 13481e5376a4bc64e8d290df79c2b6f94cccac81..dafb918620638152675fdfa69bb6489963a7e62d 100644 (file)
--- a/tests/lib/buf.c
+++ b/tests/lib/buf.c
@@ -1,3 +1,5 @@
+#define _POSIX_C_SOURCE 200809L
+#define _XOPEN_SOURCE 700
 #include <atf.h>
 #include <stdc.h>
 #include <utf.h>