binfmt_misc: fix building on windows

Signed-off-by: Tonis Tiigi <tonistiigi@gmail.com>

util/binfmt_misc/check.go

@@ -8,7 +8,6 @@ import (
 	"os"
 	"os/exec"
 	"path/filepath"
-	"syscall"
 )
 
 func check(bin string) error {
@@ -37,9 +36,7 @@ func check(bin string) error {
 	f.Close()
 
 	cmd := exec.Command("/check")
-	cmd.SysProcAttr = &syscall.SysProcAttr{
-		Chroot: tmpdir,
-	}
+	withChroot(cmd, tmpdir)
 	err = cmd.Run()
 	return err
 }

util/binfmt_misc/check_unix.go

@@ -0,0 +1,14 @@
+// +build !windows
+
+package binfmt_misc
+
+import (
+	"os/exec"
+	"syscall"
+)
+
+func withChroot(cmd *exec.Cmd, dir string) {
+	cmd.SysProcAttr = &syscall.SysProcAttr{
+		Chroot: dir,
+	}
+}

util/binfmt_misc/check_windows.go

@@ -0,0 +1,10 @@
+// +build windows
+
+package binfmt_misc
+
+import (
+	"os/exec"
+)
+
+func withChroot(cmd *exec.Cmd, dir string) {
+}