Error installing 0.10.0b1 from Github with pip
I tried installing today's release of 0.10.0.b1 in a virtualenv with:

```
pip install git+https://github.com/pydata/pandas.git
```

This fails after src/datetime:

```
i686-apple-darwin11-llvm-gcc-4.2: pandas/index.c: No such file or directory

i686-apple-darwin11-llvm-gcc-4.2: no input files

i686-apple-darwin11-llvm-gcc-4.2: pandas/index.c: No such file or directory

i686-apple-darwin11-llvm-gcc-4.2: no input files

lipo: can't figure out the architecture type of: /var/folders/cd/_zzqv0h90ms8k4s6skxvgt0w0000gp/T//cc7oTKEl.out

error: command 'llvm-gcc-4.2' failed with exit status 1
```

Should I be installing the new version of pandas in a different way?
