[cs] Added -D coreApiSerialize

std/cs/_std/Array.hx

@@ -28,6 +28,9 @@ import cs.NativeArray;
 		this.length = native.Length;
 	}
 ')
+#if coreApiSerialize
+@:meta(System.Serializable)
+#end
 @:final @:coreApi class Array<T> implements ArrayAccess<T> {
 
 	public var length(default,null) : Int;

std/cs/_std/Date.hx

@@ -24,6 +24,9 @@ import cs.system.DateTime;
 import cs.system.TimeSpan;
 import haxe.Int64;
 
+#if coreApiSerialize
+@:meta(System.Serializable)
+#end
 @:coreApi class Date
 {
 	private var date:DateTime;

std/cs/internal/HxObject.hx

@@ -33,6 +33,9 @@ private interface IHxObject
 {
 }
 
+#if coreApiSerialize
+@:meta(System.Serializable)
+#end
 @:keep @:native('haxe.lang.DynamicObject')
 private class DynamicObject extends HxObject implements Dynamic
 {
@@ -66,6 +69,9 @@ private class DynamicObject extends HxObject implements Dynamic
 
 @:native('haxe.lang.Enum')
 @:keep @:skipCtor
+#if coreApiSerialize
+@:meta(System.Serializable)
+#end
 private class Enum
 {
 	@:readOnly private var index:Int;

std/cs/internal/Null.hx

@@ -37,6 +37,9 @@ package cs.internal;
 		}
 	}
 ')
+#if coreApiSerialize
+@:meta(System.Serializable)
+#end
 @:keep @:struct @:nativeGen @:native("haxe.lang.Null") private class Nullable<T>
 {
 
@@ -84,4 +87,4 @@ package cs.internal;
 	{
 		return null;
 	}
-}
+}