btrfsck.o: In function `maybe_free_inode_rec':
btrfsck.c:(.text+0xce6): undefined reference to `S_ISDIR'
btrfsck.c:(.text+0xd13): undefined reference to `S_ISREG'
btrfsck.c:(.text+0xdc7): undefined reference to `S_ISREG'
btrfsck.c:(.text+0xe2e): undefined reference to `S_ISLNK'
btrfsck.c:(.text+0xe5b): undefined reference to `S_ISLNK'

--- btrfsck.c
+++ btrfsck.c
@@ -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"