sysutils/container-diff: Fix build on aarch64

Import upstream patch to fix this error:
  # github.com/GoogleContainerTools/container-diff/vendor/golang.org/x/sys/unix
  vendor/golang.org/x/sys/unix/ztypes_freebsd_arm64.go:400:12: undefined: uint128

Approved by:	portmgr (build fix blanket)

sysutils/container-diff/files/patch-vendor_golang.org_x_sys_unix_ztypes__freebsd__arm64.go

@@ -0,0 +1,24 @@
+From 33540a1f603772f9d4b761f416f5c10dade23e96 Mon Sep 17 00:00:00 2001
+From: Tobias Klauser <tklauser@distanz.ch>
+Date: Fri, 25 Oct 2019 21:13:51 +0200
+Subject: [PATCH] unix: don't use non-existing uint128 type on freebsd/arm64
+
+CL 179099 introduced type FpReg on freebsd, on freebsd/arm64 using a
+type uint128. This type doesn't exist in Go.
+
+Change-Id: Ie7f065f38f2cc2c163abdfa7dddad886b8edbe3b
+Reviewed-on: https://go-review.googlesource.com/c/sys/+/203419
+Run-TryBot: Tobias Klauser <tobias.klauser@gmail.com>
+TryBot-Result: Gobot Gobot <gobot@golang.org>
+Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
+--- vendor/golang.org/x/sys/unix/ztypes_freebsd_arm64.go.orig	2019-08-18 13:42:05 UTC
++++ vendor/golang.org/x/sys/unix/ztypes_freebsd_arm64.go
+@@ -397,7 +397,7 @@ type Reg struct {
+ }
+ 
+ type FpReg struct {
+-	Fp_q  [32]uint128
++	Fp_q  [512]uint8
+ 	Fp_sr uint32
+ 	Fp_cr uint32
+ }