all: go fmt ./...

Make all our package sources use Go 1.17 gofmt format
(adding //go:build lines).

Not strictly necessary but will avoid spurious changes
as files are edited.

Part of //go:build change (#41184).
See https://golang.org/design/draft-gobuild

Change-Id: I01667f826428426a39c84717d02efa25fa44553c
Reviewed-on: https://go-review.googlesource.com/c/sys/+/294490
TryBot-Result: Go Bot <gobot@golang.org>
Reviewed-by: Keith Randall <khr@golang.org>
Reviewed-by: Josh Bleecher Snyder <josharian@gmail.com>
Reviewed-by: Matt Layher <mdlayher@gmail.com>
Trust: Josh Bleecher Snyder <josharian@gmail.com>
Trust: Russ Cox <rsc@golang.org>
Run-TryBot: Josh Bleecher Snyder <josharian@gmail.com>
Run-TryBot: Russ Cox <rsc@golang.org>
diff --git a/unix/endian_big.go b/unix/endian_big.go
index 86781ea..a520265 100644
--- a/unix/endian_big.go
+++ b/unix/endian_big.go
@@ -2,6 +2,7 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 //
+//go:build armbe || arm64be || m68k || mips || mips64 || mips64p32 || ppc || ppc64 || s390 || s390x || shbe || sparc || sparc64
 // +build armbe arm64be m68k mips mips64 mips64p32 ppc ppc64 s390 s390x shbe sparc sparc64
 
 package unix