diff --git a/lib/h264.cpp b/lib/h264.cpp
index 97bd6320..20d961b8 100644
--- a/lib/h264.cpp
+++ b/lib/h264.cpp
@@ -1,3 +1,4 @@
+#define _GNU_SOURCE
 #include "h264.h"
 #include <cstdlib>
 #include <cstring>
diff --git a/lib/nal.cpp b/lib/nal.cpp
index 3ba793b8..a28edd23 100644
--- a/lib/nal.cpp
+++ b/lib/nal.cpp
@@ -1,3 +1,4 @@
+#define _GNU_SOURCE
 #include <cstdlib>
 #include <cstring>
 #include <math.h>//for log