[AltDaemon] Replaces local socket communication with XPC

Allows AltDaemon to be launched on demand + reject any connections not made from AltStore.

Shared/Extensions/NSXPCConnection+MachServices.swift

@@ -0,0 +1,33 @@
+//
+//  NSXPCConnection+MachServices.swift
+//  AltStore
+//
+//  Created by Riley Testut on 9/22/20.
+//  Copyright © 2020 Riley Testut. All rights reserved.
+//
+
+import Foundation
+
+@objc private protocol XPCPrivateAPI
+{
+    init(machServiceName: String)
+    init(machServiceName: String, options: NSXPCConnection.Options)
+}
+
+public extension NSXPCConnection
+{
+    class func makeConnection(machServiceName: String) -> NSXPCConnection
+    {
+        let connection = unsafeBitCast(self, to: XPCPrivateAPI.Type.self).init(machServiceName: machServiceName, options: .privileged)
+        return unsafeBitCast(connection, to: NSXPCConnection.self)
+    }
+}
+
+public extension NSXPCListener
+{
+    class func makeListener(machServiceName: String) -> NSXPCListener
+    {
+        let listener = unsafeBitCast(self, to: XPCPrivateAPI.Type.self).init(machServiceName: machServiceName)
+        return unsafeBitCast(listener, to: NSXPCListener.self)
+    }
+}