diff --git a/acme.go b/acme.go
index a0a3a2fe..5a3a4d62 100644
--- a/acme.go
+++ b/acme.go
@@ -2,8 +2,8 @@ package main
 
 import (
 	"context"
+	"errors"
 	"flag"
-	"fmt"
 	"image"
 	"log"
 	"os"
@@ -577,7 +577,7 @@ type errorWriter struct{}
 func (w errorWriter) Write(data []byte) (n int, err error) {
 	n = len(data)
 	if n > 0 {
-		global.cerr <- fmt.Errorf(string(data))
+		global.cerr <- errors.New(string(data))
 	}
 	return
 }
diff --git a/cmd/win/win_unix.go b/cmd/win/win_unix.go
index 0527ee63..6d57c53f 100644
--- a/cmd/win/win_unix.go
+++ b/cmd/win/win_unix.go
@@ -1,4 +1,3 @@
-// go:build (darwin || dragonfly || freebsd || linux || netbsd || openbsd || solaris)
 //go:build darwin || dragonfly || freebsd || linux || netbsd || openbsd || solaris
 // +build darwin dragonfly freebsd linux netbsd openbsd solaris