define haxe5

Author: Simn

src/compiler/compiler.ml

@@ -233,6 +233,7 @@ module Setup = struct
 		Common.define_value com Define.HaxeVer (Printf.sprintf "%.3f" (float_of_int Globals.version /. 1000.));
 		Common.raw_define com "haxe3";
 		Common.raw_define com "haxe4";
+		Common.raw_define com "haxe5";
 		Common.define_value com Define.Haxe s_version;
 		Common.raw_define com "true";
 		Common.define_value com Define.Dce "std";