fix build break for plan9

terminal_check_windows.go

@@ -6,15 +6,29 @@ import (
 	"io"
 	"os"
 	"syscall"
+
+	sequences "github.com/konsorten/go-windows-terminal-sequences"
 )
 
+func initTerminal(w io.Writer) {
+	switch v := w.(type) {
+	case *os.File:
+		sequences.EnableVirtualTerminalProcessing(syscall.Handle(v.Fd()), true)
+	}
+}
+
 func checkIfTerminal(w io.Writer) bool {
+	var ret bool
 	switch v := w.(type) {
 	case *os.File:
 		var mode uint32
 		err := syscall.GetConsoleMode(syscall.Handle(v.Fd()), &mode)
-		return err == nil
+		ret = (err == nil)
 	default:
-		return false
+		ret = false
 	}
+	if ret {
+		initTerminal(w)
+	}
+	return ret
 }