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: I70526bf588bf4078887e567795867ece785d666b
Reviewed-on: https://go-review.googlesource.com/c/crypto/+/294415
Trust: Russ Cox <rsc@golang.org>
Run-TryBot: Russ Cox <rsc@golang.org>
TryBot-Result: Go Bot <gobot@golang.org>
Reviewed-by: Jason A. Donenfeld <Jason@zx2c4.com>
Reviewed-by: Ian Lance Taylor <iant@golang.org>

chacha20poly1305/chacha20poly1305_amd64.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 gc && !purego
 // +build gc,!purego
 
 package chacha20poly1305

chacha20poly1305/chacha20poly1305_noasm.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 !amd64 || !gc || purego
 // +build !amd64 !gc purego
 
 package chacha20poly1305