Adopting LLVM for Reactos/XP/Server2003: Need Help

We are working on a SDK for Reactos/XP/2003, since NT5.1/5.2 to doesn’t native support for certain NT6 , we have fixed all of them and even ported LibC++ successfully to older Win32 architecture ,
problem is LLVM handle memcpy which is used by our implementation of GetFinalPathNameByHandleW , though it compiles standalone in Visual Studio but causes series of error which might be related to CMAKE.
We hope some senior developer alike can show us some path , it is last hurdle to get newer LLVM on NT5.
Our Core developer who goes by alias “barcode” is baffled by the error and has an experiences of 25yrs.

Since I am new user i cannot attach code here , so i would love if liberty provided for once.

I hope its readable , i have uploaded here on Github