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>