Fix a compile error on recent systems

diff --git a/src/misclibs/rbtree/rbtree.h b/src/misclibs/rbtree/rbtree.h
index a4e4c3b8fe5c88ebb1421f1ab3704bbe5e078322..8446e96c36fb20acc80cc99832840c21a98e5426 100644 (file)
--- a/src/misclibs/rbtree/rbtree.h
+++ b/src/misclibs/rbtree/rbtree.h
@@ -96,6 +96,7 @@ static inline struct page * rb_insert_page_cache(struct inode * inode,
 
 #include <linux/kernel.h>
 #include <linux/stddef.h>
+#include <stddef.h>            /* For NULL */
 
 #ifdef __cplusplus
 extern "C" {