This problem is because the vcvars.bat file fails if your path env variable has any path segments with double quotes in it.
so if your PATH variable looks like this:
PATH="c:\program files (x86)\Microsoft Visual Studio 12.0\Common7\IDE"
the build will fail
just take the double quotes out (they aren’t needed):
PATH=c:\program files (x86)\Microsoft Visual Studio 12.0\Common7\IDE