libyang BUGFIX set feature macro for strdup() on OSX
Since OS X requires different value (600) of _XOPEN_SOURCE feature test macro for
strdup() than linux (500), better use _POSIX_C_SOURCE 200809L. It is available
since glibc 2.12 (released 2010) so it shouldn't be an issue.
diff --git a/tests/utests/test_xml.c b/tests/utests/test_xml.c
index 89a8ce8..a4dee59 100644
--- a/tests/utests/test_xml.c
+++ b/tests/utests/test_xml.c
@@ -14,6 +14,7 @@
#define _DEFAULT_SOURCE
#define _GNU_SOURCE
+#define _POSIX_C_SOURCE 200809L /* strdup */
#include <stdarg.h>
#include <stddef.h>