build: add imports for go generate tools (#24682)

This adds a tools.go file to import all command packages used for
go:generate. Doing so makes it possible to execute go-based code
generators using 'go run', locking in the tool version using go.mod.

Co-authored-by: Felix Lange <fjl@twurst.com>

cmd/evm/internal/t8ntool/block.go

@@ -36,7 +36,7 @@ import (
 	"gopkg.in/urfave/cli.v1"
 )
 
-//go:generate gencodec -type header -field-override headerMarshaling -out gen_header.go
+//go:generate go run github.com/fjl/gencodec -type header -field-override headerMarshaling -out gen_header.go
 type header struct {
 	ParentHash  common.Hash       `json:"parentHash"`
 	OmmerHash   *common.Hash      `json:"sha3Uncles"`

cmd/evm/internal/t8ntool/execution.go

@@ -63,7 +63,7 @@ type ommer struct {
 	Address common.Address `json:"address"`
 }
 
-//go:generate gencodec -type stEnv -field-override stEnvMarshaling -out gen_stenv.go
+//go:generate go run github.com/fjl/gencodec -type stEnv -field-override stEnvMarshaling -out gen_stenv.go
 type stEnv struct {
 	Coinbase         common.Address                      `json:"currentCoinbase"   gencodec:"required"`
 	Difficulty       *big.Int                            `json:"currentDifficulty"`

cmd/faucet/faucet.go

@@ -17,7 +17,7 @@
 // faucet is an Ether faucet backed by a light client.
 package main
 
-//go:generate go-bindata -nometadata -o website.go faucet.html
+//go:generate go run github.com/kevinburke/go-bindata/go-bindata -nometadata -o website.go faucet.html
 //go:generate gofmt -w -s website.go
 
 import (

cmd/faucet/website.go

@@ -20,7 +20,7 @@ import (
 func bindataRead(data []byte, name string) ([]byte, error) {
 	gz, err := gzip.NewReader(bytes.NewBuffer(data))
 	if err != nil {
-		return nil, fmt.Errorf("read %q: %v", name, err)
+		return nil, fmt.Errorf("read %q: %w", name, err)
 	}
 
 	var buf bytes.Buffer
@@ -28,7 +28,7 @@ func bindataRead(data []byte, name string) ([]byte, error) {
 	clErr := gz.Close()
 
 	if err != nil {
-		return nil, fmt.Errorf("read %q: %v", name, err)
+		return nil, fmt.Errorf("read %q: %w", name, err)
 	}
 	if clErr != nil {
 		return nil, err
@@ -183,6 +183,9 @@ var _bindata = map[string]func() (*asset, error){
 	"faucet.html": faucetHtml,
 }
 
+// AssetDebug is true if the assets were built with the debug flag enabled.
+const AssetDebug = false
+
 // AssetDir returns the file names below a certain
 // directory embedded in the file by go-bindata.
 // For example if you run go-bindata on data/... and data contains the