Revert "cmd/cgo, cmd/compile, cmd/link: remove old style build tags"

This reverts commit 6616573, corresponding to CL 436915.

Reason for revert: this is causing some bootstrap build problems with older versions of Go 1.17, as I understand it. Still under investigation.

Change-Id: Idb6e17ff7b47004cbf87f967af6d84f214d8abb5
Reviewed-on: https://go-review.googlesource.com/c/go/+/435471
Reviewed-by: David Chase <[email protected]>

src/cmd/cgo/ast_go1.go

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

src/cmd/cgo/ast_go118.go

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

src/cmd/compile/internal/base/bootstrap_false.go

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

src/cmd/compile/internal/base/bootstrap_true.go

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

src/cmd/compile/internal/base/mapfile_mmap.go

@@ -3,6 +3,7 @@
 // license that can be found in the LICENSE file.
 
 //go:build darwin || dragonfly || freebsd || linux || netbsd || openbsd || (solaris && go1.20)
+// +build darwin dragonfly freebsd linux netbsd openbsd solaris,go1.20
 
 package base
 

src/cmd/compile/internal/base/mapfile_read.go

@@ -3,6 +3,13 @@
 // license that can be found in the LICENSE file.
 
 //go:build !darwin && !dragonfly && !freebsd && !linux && !netbsd && !openbsd && !(solaris && go1.20)
+// +build !darwin
+// +build !dragonfly
+// +build !freebsd
+// +build !linux
+// +build !netbsd
+// +build !openbsd
+// +build !solaris !go1.20
 
 package base
 

src/cmd/compile/internal/ir/mknode.go

@@ -3,6 +3,7 @@
 // license that can be found in the LICENSE file.
 
 //go:build ignore
+// +build ignore
 
 // Note: this program must be run in this directory.
 //   go run mknode.go

src/cmd/compile/internal/ssa/flags_test.go

@@ -3,6 +3,7 @@
 // license that can be found in the LICENSE file.
 
 //go:build amd64 || arm64
+// +build amd64 arm64
 
 package ssa
 

src/cmd/compile/internal/ssa/gen/386Ops.go

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

src/cmd/compile/internal/ssa/gen/AMD64Ops.go

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

src/cmd/compile/internal/ssa/gen/ARM64Ops.go

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

src/cmd/compile/internal/ssa/gen/ARMOps.go

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

src/cmd/compile/internal/ssa/gen/LOONG64Ops.go

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

src/cmd/compile/internal/ssa/gen/MIPS64Ops.go

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

src/cmd/compile/internal/ssa/gen/MIPSOps.go

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

src/cmd/compile/internal/ssa/gen/PPC64Ops.go

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

src/cmd/compile/internal/ssa/gen/RISCV64Ops.go

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

src/cmd/compile/internal/ssa/gen/S390XOps.go

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

src/cmd/compile/internal/ssa/gen/WasmOps.go

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

src/cmd/compile/internal/ssa/gen/dec64Ops.go

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

src/cmd/compile/internal/ssa/gen/decOps.go

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

src/cmd/compile/internal/ssa/gen/genericOps.go

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

src/cmd/compile/internal/ssa/gen/main.go

@@ -3,6 +3,7 @@
 // license that can be found in the LICENSE file.
 
 //go:build ignore
+// +build ignore
 
 // The gen command generates Go code (in the parent directory) for all
 // the architecture-specific opcodes, blocks, and rewrites.

src/cmd/compile/internal/ssa/gen/rulegen.go

@@ -3,6 +3,7 @@
 // license that can be found in the LICENSE file.
 
 //go:build gen
+// +build gen
 
 // This program generates Go code that applies rewrite rules to a Value.
 // The generated code implements a function of type func (v *Value) bool

src/cmd/compile/internal/typecheck/builtin/runtime.go

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

src/cmd/compile/internal/typecheck/mkbuiltin.go

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

src/cmd/compile/internal/types2/example_test.go

@@ -6,6 +6,7 @@
 // access to compiled packages for import.
 //
 //go:build !arm && !arm64
+// +build !arm,!arm64
 
 package types2_test
 

src/cmd/internal/bio/buf_mmap.go

@@ -3,6 +3,7 @@
 // license that can be found in the LICENSE file.
 
 //go:build darwin || dragonfly || freebsd || linux || netbsd || openbsd || (solaris && go1.20)
+// +build darwin dragonfly freebsd linux netbsd openbsd solaris,go1.20
 
 package bio
 

src/cmd/internal/bio/buf_nommap.go

@@ -3,6 +3,13 @@
 // license that can be found in the LICENSE file.
 
 //go:build !darwin && !dragonfly && !freebsd && !linux && !netbsd && !openbsd && !(solaris && go1.20)
+// +build !darwin
+// +build !dragonfly
+// +build !freebsd
+// +build !linux
+// +build !netbsd
+// +build !openbsd
+// +build !solaris !go1.20
 
 package bio
 

src/cmd/link/elf_test.go

@@ -3,6 +3,7 @@
 // license that can be found in the LICENSE file.
 
 //go:build dragonfly || freebsd || linux || netbsd || openbsd
+// +build dragonfly freebsd linux netbsd openbsd
 
 package main
 

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

@@ -3,6 +3,7 @@
 // license that can be found in the LICENSE file.
 
 //go:build aix || darwin || dragonfly || freebsd || linux || netbsd || openbsd || (solaris && go1.20)
+// +build aix darwin dragonfly freebsd linux netbsd openbsd solaris,go1.20
 
 package ld
 

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

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

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

@@ -3,6 +3,15 @@
 // license that can be found in the LICENSE file.
 
 //go:build !aix && !darwin && !dragonfly && !freebsd && !linux && !netbsd && !openbsd && !(solaris && go1.20) && !windows
+// +build !aix
+// +build !darwin
+// +build !dragonfly
+// +build !freebsd
+// +build !linux
+// +build !netbsd
+// +build !openbsd
+// +build !solaris !go1.20
+// +build !windows
 
 package ld