Linux 5.1 (commit 6cc248684d3d) renames DCACHE_ENCRYPTED_WITH_KEY to
DCACHE_ENCRYPTED_NAME.

--- a/libcfs/include/libcfs/crypto/llcrypt.h
+++ b/libcfs/include/libcfs/crypto/llcrypt.h
@@ -13,6 +13,10 @@
 #ifndef _LINUX_LLCRYPT_H
 #define _LINUX_LLCRYPT_H
 
+#ifndef DCACHE_ENCRYPTED_NAME
+#define DCACHE_ENCRYPTED_NAME 0x02000000
+#endif
+
 #include <linux/fs.h>
 #include <linux/mm.h>
 #include <linux/slab.h>