[AltServer] Supports changing AltJIT timeout via defaults CLI

AltServer/Extensions/UserDefaults+AltServer.swift

@@ -36,3 +36,16 @@ extension UserDefaults
         }
     }
 }
+
+// "Public" defaults configurable via CLI.
+extension UserDefaults
+{
+    private static let altJITTimeoutKey = "JITTimeout"
+    
+    var altJITTimeout: TimeInterval? {
+        let timeout = self.double(forKey: UserDefaults.altJITTimeoutKey) // Coerces strings into doubles.
+        guard timeout != 0 else { return nil }
+        
+        return timeout
+    }
+}

AltServer/JIT/JITManager.swift

@@ -137,6 +137,11 @@ private extension JITManager
             }
             arguments += ["--udid", device.identifier]
             
+            if let timeout = UserDefaults.standard.altJITTimeout
+            {
+                arguments += ["--timeout", String(timeout)]
+            }
+            
             self.authorization = try Process.runAsAdmin(URL.altjit.path, arguments: arguments, authorization: self.authorization)
         }
         catch