You need to use a version of the cl.exe compiler which emits x64 code. Which one depends a bit on your setup.
Let’s consider the case you’re on a 64 bit machine. For this you’ll need to use the compiler which lives at
c:\Program Files (x86)\Microsoft visual Studio 10.0\VC\bin\amd64\cl.exe
If you’re on a 32 bit machine you’ll need to use the cross compiler located at
c:\Program Files\Microsoft Visual Studio 10.0\VC\bin\x86_amd64\cl.exe