Use the x86_amd64 compiler. by using
call "C:\Program Files (x86)\Microsoft Visual Studio 14.0\VC\vcvarsall.bat" x86_amd64
x86_amd64 is the same compiler emitting 64-bit library code, but the compiler itself is 32-bit. Ran into the issue with the line (compiler file 'f:\dd\vctools\compiler\utc\src\p2\main.c', line 255)
couple of times in different code bases and the above workaround worked both times.