diff --git a/src/generic/util/dirent_safe.h b/src/generic/util/dirent_safe.h
index 5c83c2c..ab42e7f 100644
--- a/src/generic/util/dirent_safe.h
+++ b/src/generic/util/dirent_safe.h
@@ -20,6 +20,7 @@
 #ifndef DIRENT_SAFE_H
 #define DIRENT_SAFE_H
 
+#include <stddef.h>
 #include <dirent.h>
 
 /** \brief A version of dirent that's safe to use with readdir_r