add vendoring with go dep

vendor/golang.org/x/net/lif/sys.go

@@ -0,0 +1,21 @@
+// 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.
+
+// +build solaris
+
+package lif
+
+import "unsafe"
+
+var nativeEndian binaryByteOrder
+
+func init() {
+	i := uint32(1)
+	b := (*[4]byte)(unsafe.Pointer(&i))
+	if b[0] == 1 {
+		nativeEndian = littleEndian
+	} else {
+		nativeEndian = bigEndian
+	}
+}