support -ldflags=main.version= again

I rolled back the build via the proxy in my go-cross build script,
as that sort of thing is incompatible with how many packagers and
distributions automatically build Go software.

Fixes #253 again.

format/format.go

@@ -395,7 +395,7 @@ func (f *fumpter) applyPre(c *astutil.Cursor) {
 					slc := []string{
 						"//gofumpt:diagnose",
 						"version:",
-						version.String(),
+						version.String(""),
 						"flags:",
 						"-lang=" + f.LangVersion,
 						"-modpath=" + f.ModulePath,

gofmt.go

@@ -30,7 +30,7 @@ import (
 	gformat "mvdan.cc/gofumpt/format"
 	"mvdan.cc/gofumpt/internal/govendor/diff"
 	"mvdan.cc/gofumpt/internal/govendor/go/printer"
-	"mvdan.cc/gofumpt/internal/version"
+	gversion "mvdan.cc/gofumpt/internal/version"
 )
 
 //go:generate go run gen_govendor.go
@@ -57,6 +57,8 @@ var (
 	simplifyAST = flag.Bool("s", false, "")
 )
 
+var version = ""
+
 // Keep these in sync with go/format/format.go.
 const (
 	tabWidth    = 8
@@ -464,7 +466,7 @@ func gofmtMain(s *sequencer) {
 
 	// Print the gofumpt version if the user asks for it.
 	if *showVersion {
-		fmt.Println(version.String())
+		fmt.Println(gversion.String(version))
 		return
 	}
 

internal/version/version.go

@@ -97,6 +97,9 @@ func goVersion() string {
 	return runtime.Version()
 }
 
-func String() string {
+func String(injected string) string {
+	if injected != "" {
+		return fmt.Sprintf("%s (%s)", injected, goVersion())
+	}
 	return fmt.Sprintf("%s (%s)", gofumptVersion(), goVersion())
 }