all: drop old +build lines

Running 'go fix' on the cmd+std packages handled much of this change.

Also update code generators to use only the new go:build lines,
not the old +build ones.

For #41184.
For #60268.

Change-Id: If35532abe3012e7357b02c79d5992ff5ac37ca23
Cq-Include-Trybots: luci.golang.try:gotip-linux-386-longtest,gotip-linux-amd64-longtest,gotip-windows-amd64-longtest
Reviewed-on: https://go-review.googlesource.com/c/go/+/536237
Reviewed-by: Ian Lance Taylor <iant@google.com>
Reviewed-by: Dmitri Shuralyov <dmitshur@google.com>
Auto-Submit: Dmitri Shuralyov <dmitshur@golang.org>
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>

Author: dmitshur

src/cmd/compile/internal/ssa/_gen/cover.bash

@@ -12,7 +12,7 @@
 # regular 'go run .' usage to run the generator.
 
 cat >main_test.go <<-EOF
-	// +build ignore
+	//go:build ignore
 
 	package main
 

src/cmd/compile/internal/typecheck/_builtin/coverage.go

@@ -7,7 +7,6 @@
 // to avoid depending on having a working compiler binary.
 
 //go:build ignore
-// +build ignore
 
 package coverage
 

src/cmd/dist/notgo120.go

@@ -17,6 +17,5 @@
 // why Go moved on from Go 1.4 for bootstrap.
 
 //go:build !go1.20
-// +build !go1.20
 
 package building_Go_requires_Go_1_20_6_or_later

src/cmd/dist/sys_default.go

@@ -3,7 +3,6 @@
 // license that can be found in the LICENSE file.
 
 //go:build !windows
-// +build !windows
 
 package main
 

src/cmd/dist/util_gc.go

@@ -3,7 +3,6 @@
 // license that can be found in the LICENSE file.
 
 //go:build gc
-// +build gc
 
 package main
 

src/cmd/dist/util_gccgo.go

@@ -3,7 +3,6 @@
 // license that can be found in the LICENSE file.
 
 //go:build gccgo
-// +build gccgo
 
 package main
 

src/cmd/dist/vfp_arm.s

@@ -3,7 +3,6 @@
 // license that can be found in the LICENSE file.
 
 //go:build gc
-// +build gc
 
 #include "textflag.h"
 

src/cmd/dist/vfp_default.s

@@ -3,7 +3,6 @@
 // license that can be found in the LICENSE file.
 
 //go:build gc && !arm
-// +build gc,!arm
 
 #include "textflag.h"
 

src/cmd/go/internal/modcmd/vendor.go

@@ -299,7 +299,7 @@ func vendorPkg(vdir, pkg string) {
 	// a MultiplePackageError on an otherwise valid package: the package could
 	// have different names for GOOS=windows and GOOS=mac for example. On the
 	// other hand if there's a NoGoError, the package might have source files
-	// specifying "// +build ignore" those packages should be skipped because
+	// specifying "//go:build ignore" those packages should be skipped because
 	// embeds from ignored files can't be used.
 	// TODO(#42504): Find a better way to avoid errors from ImportDir. We'll
 	// need to figure this out when we switch to PackagesAndErrors as per the

src/cmd/go/internal/modload/import.go

@@ -706,7 +706,7 @@ func dirInModule(path, mpath, mdir string, isLocal bool) (dir string, haveGoFile
 	// Now committed to returning dir (not "").
 
 	// Are there Go source files in the directory?
-	// We don't care about build tags, not even "+build ignore".
+	// We don't care about build tags, not even "go:build ignore".
 	// We're just looking for a plausible directory.
 	haveGoFiles, err = haveGoFilesCache.Do(dir, func() (bool, error) {
 		// modindex.GetPackage will return ErrNotIndexed for any directories which

src/cmd/internal/goobj/mkbuiltin.go

@@ -3,7 +3,6 @@
 // license that can be found in the LICENSE file.
 
 //go:build ignore
-// +build ignore
 
 // Generate builtinlist.go from cmd/compile/internal/typecheck/builtin/runtime.go.
 

src/cmd/internal/notsha256/sha256block_386.s

@@ -3,7 +3,6 @@
 // license that can be found in the LICENSE file.
 
 //go:build !purego
-// +build !purego
 
 // SHA256 block routine. See sha256block.go for Go equivalent.
 //

src/cmd/internal/notsha256/sha256block_amd64.go

@@ -3,7 +3,6 @@
 // license that can be found in the LICENSE file.
 
 //go:build !purego
-// +build !purego
 
 package notsha256
 

src/cmd/internal/notsha256/sha256block_amd64.s

@@ -3,7 +3,6 @@
 // license that can be found in the LICENSE file.
 
 //go:build !purego
-// +build !purego
 
 #include "textflag.h"
 

src/cmd/internal/notsha256/sha256block_decl.go

@@ -3,8 +3,6 @@
 // license that can be found in the LICENSE file.
 
 //go:build !purego && (386 || amd64 || ppc64le || ppc64)
-// +build !purego
-// +build 386 amd64 ppc64le ppc64
 
 package notsha256
 

src/cmd/internal/notsha256/sha256block_generic.go

@@ -3,7 +3,6 @@
 // license that can be found in the LICENSE file.
 
 //go:build purego || (!amd64 && !386 && !ppc64le && !ppc64)
-// +build purego !amd64,!386,!ppc64le,!ppc64
 
 package notsha256
 

src/cmd/internal/notsha256/sha256block_ppc64x.s

@@ -9,8 +9,6 @@
 //
 
 //go:build !purego && (ppc64 || ppc64le)
-// +build !purego
-// +build ppc64 ppc64le
 
 // Based on CRYPTOGAMS code with the following comment:
 // # ====================================================================

src/cmd/internal/obj/stringer.go

@@ -3,7 +3,6 @@
 // license that can be found in the LICENSE file.
 
 //go:build ignore
-// +build ignore
 
 // This is a mini version of the stringer tool customized for the Anames table
 // in the architecture support for obj.

src/cmd/link/internal/ld/elf_test.go

@@ -3,7 +3,6 @@
 // license that can be found in the LICENSE file.
 
 //go:build cgo
-// +build cgo
 
 package ld
 

src/cmd/link/internal/ld/execarchive.go

@@ -3,7 +3,6 @@
 // license that can be found in the LICENSE file.
 
 //go:build !wasm && !windows
-// +build !wasm,!windows
 
 package ld
 

src/cmd/link/internal/ld/execarchive_noexec.go

@@ -3,7 +3,6 @@
 // license that can be found in the LICENSE file.
 
 //go:build wasm || windows
-// +build wasm windows
 
 package ld
 

src/crypto/boring/notboring_test.go

@@ -3,7 +3,6 @@
 // license that can be found in the LICENSE file.
 
 //go:build (goexperiment.boringcrypto && !boringcrypto) || (!goexperiment.boringcrypto && boringcrypto)
-// +build goexperiment.boringcrypto,!boringcrypto !goexperiment.boringcrypto,boringcrypto
 
 package boring_test
 

src/crypto/internal/boring/sig/sig_other.s

@@ -8,7 +8,6 @@
 // On other platforms (those using this source file), they don't.
 
 //go:build !amd64
-// +build !amd64
 
 TEXT ·BoringCrypto(SB),$0
 	RET

src/crypto/internal/edwards25519/field/fe_arm64.s

@@ -2,7 +2,7 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
-// +build arm64,gc,!purego
+//go:build arm64 && gc && !purego
 
 #include "textflag.h"