Fix for Linux/Android

Author: guykogus

Sources/JSONDecoder.swift

@@ -828,8 +828,10 @@ private func decodeDateFromJSON(
             let formatter = ISO8601DateFormatter()
             if let date = formatter.date(from: value) { return date }
         }
+    #if !os(Linux) && !os(Android)
     case let .formatted(formatter):
         if case let .string(value) = json, let date = formatter.date(from: value) { return date }
+    #endif
     case let .custom(block):
         return try block(JSONDecoderImpl(
             codingPath: path,