missing include in btrfsck.c

Hello everybody,

compiling btrfs-progs from current git I get an error in btrfsck.c about undefined references. The attached patch adds an include for sys/stat.h which fixes the problem for me.

Regards,
Chris

@@ -21,6 +21,7 @@
 #include <stdio.h>
 #include <stdlib.h>
 #include <fcntl.h>
+#include <sys/stat.h>
 #include "kerncompat.h"
 #include "ctree.h"
 #include "disk-io.h"