diff --git a/vendor/golang.org/x/sys/unix/dev_dragonfly.go b/vendor/golang.org/x/sys/unix/dev_dragonfly.go
new file mode 100644
index 0000000..8502f20
--- /dev/null
+++ b/vendor/golang.org/x/sys/unix/dev_dragonfly.go
@@ -0,0 +1,30 @@
+// Copyright 2017 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// Functions to access/create device major and minor numbers matching the
+// encoding used in Dragonfly's sys/types.h header.
+//
+// The information below is extracted and adapted from sys/types.h:
+//
+// Minor gives a cookie instead of an index since in order to avoid changing the
+// meanings of bits 0-15 or wasting time and space shifting bits 16-31 for
+// devices that don't use them.
+
+package unix
+
+// Major returns the major component of a DragonFlyBSD device number.
+func Major(dev uint64) uint32 {
+	return uint32((dev >> 8) & 0xff)
+}
+
+// Minor returns the minor component of a DragonFlyBSD device number.
+func Minor(dev uint64) uint32 {
+	return uint32(dev & 0xffff00ff)
+}
+
+// Mkdev returns a DragonFlyBSD device number generated from the given major and
+// minor components.
+func Mkdev(major, minor uint32) uint64 {
+	return (uint64(major) << 8) | uint64(minor)
+}