FD reviving

Author: JkLondon

mdbx/env_windows.go

@@ -30,8 +30,8 @@ func (env *Env) FD() (uintptr, error) {
 	// to avoid constant value overflow errors at compile time.
 	const fdInvalid = ^uintptr(0)
 
-	mf := new(C.mdbx_filehandle_t)
-	ret := C.mdbx_env_get_fd(env._env, mf)
+	var fh C.mdbx_filehandle_t
+	ret := C.mdbx_env_get_fd(env._env, fh)
 	err := operrno("mdbx_env_get_fd", ret)
 	if err != nil {
 		return 0, err