portlist: fix build tag to build only on macOS, not macOS+iOS.

portlist/portlist_macos.go

@@ -2,8 +2,8 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
-//go:build darwin
-// +build darwin
+//go:build darwin && !ios
+// +build darwin,!ios
 
 package portlist