C++11 in Windows Phone 8.0 project

currently I have to port an existing mobile application which runs on Android and IOS to Windows 8. Unfortunately it is using a lot of C++11 Stuff, which is not supported by Windows Phone 8.0. The project itself was written with cocos2d-x 2.0. It contains a C# Part which loads a C++ library with the major part of the application. Also it includes modules from "Project Angle", which is a library to convert OpenGL calls into DirectX calls.

The first thing I tried was to upgrade the project to Windows Phone 8.1 using the 'reassign project' option from Visual Studio. I still had to remove a bit of C++11 Code, but now at least the project itself compiles. After compiling I got some linker errors for functions like 'getenv'. The angle libraries don't even compile and gives me errors like 'Cant find include file vccorlib.h' for every single source file. Since I'm completely new to Windows development, I don't know if something went wrong on upgrading the projects, or if I have to fix something within the projects. But I tried to upgrade an other project, which was already ported to WP8, and got the same errors.

Now I have to deceide if I have to fix the Windows Phone 8.1 version or if it's easier to remove C++11 Code for 8.0 (which means a few days of work and let my heart bleed)

I also found a compiler update for Visual Studio 2012, which has extended support for C++11, but it seems it's not compatible for Windows Phone.

I hope someone of you could give me a hint, what I have missed for WP 8.1 or has another idea. Thanks for your help!