Revert "rlp/rlpgen: remove build tag (#28106)"

This reverts commit ec2a2276b2.

core/types/gen_account_rlp.go

@@ -1,5 +1,8 @@
 // Code generated by rlpgen. DO NOT EDIT.
 
+//go:build !norlpgen
+// +build !norlpgen
+
 package types
 
 import "github.com/ethereum/go-ethereum/rlp"

core/types/gen_header_rlp.go

@@ -1,5 +1,8 @@
 // Code generated by rlpgen. DO NOT EDIT.
 
+//go:build !norlpgen
+// +build !norlpgen
+
 package types
 
 import "github.com/ethereum/go-ethereum/rlp"

core/types/gen_log_rlp.go

@@ -1,5 +1,8 @@
 // Code generated by rlpgen. DO NOT EDIT.
 
+//go:build !norlpgen
+// +build !norlpgen
+
 package types
 
 import "github.com/ethereum/go-ethereum/rlp"

core/types/gen_withdrawal_rlp.go

@@ -1,5 +1,8 @@
 // Code generated by rlpgen. DO NOT EDIT.
 
+//go:build !norlpgen
+// +build !norlpgen
+
 package types
 
 import "github.com/ethereum/go-ethereum/rlp"

rlp/rlpgen/main.go

@@ -73,8 +73,9 @@ type Config struct {
 func (cfg *Config) process() (code []byte, err error) {
 	// Load packages.
 	pcfg := &packages.Config{
-		Mode: packages.NeedName | packages.NeedTypes,
+		Mode:       packages.NeedName | packages.NeedTypes | packages.NeedImports | packages.NeedDeps,
 		Dir:        cfg.Dir,
+		BuildFlags: []string{"-tags", "norlpgen"},
 	}
 	ps, err := packages.Load(pcfg, pathOfPackageRLP, ".")
 	if err != nil {
@@ -116,6 +117,8 @@ func (cfg *Config) process() (code []byte, err error) {
 	// This is done here to avoid processing these lines with gofmt.
 	var header bytes.Buffer
 	fmt.Fprint(&header, "// Code generated by rlpgen. DO NOT EDIT.\n\n")
+	fmt.Fprint(&header, "//go:build !norlpgen\n")
+	fmt.Fprint(&header, "// +build !norlpgen\n\n")
 	return append(header.Bytes(), code...), nil
 }