lib/connections: Add KCP support (fixes #804)

GitHub-Pull-Request: https://github.com/syncthing/syncthing/pull/3489

vendor/github.com/klauspost/crc32/crc32_otherarch.go

@@ -0,0 +1,15 @@
+// Copyright 2011 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 !amd64,!amd64p32,!s390x
+
+package crc32
+
+func archAvailableIEEE() bool                    { return false }
+func archInitIEEE()                              { panic("not available") }
+func archUpdateIEEE(crc uint32, p []byte) uint32 { panic("not available") }
+
+func archAvailableCastagnoli() bool                    { return false }
+func archInitCastagnoli()                              { panic("not available") }
+func archUpdateCastagnoli(crc uint32, p []byte) uint32 { panic("not available") }