FFTW: build single precision as well
Add Julia package
Clone submodules by hand
Use latest git version

Use submodules. Download things from the internet during the build for now.
Use prefix, no dependencies

Now it builds and installs properly
Use our OpenBlas and LLVM
Merge branch 'fftw' into julia
Use our FFTW
Specify -L for openblas
Use our GMP
Use our MPFR