We need to pass `-L` to our `gfortran` in order to help it find the
system libraries without the Command Line Tools being installed.
However, this ends up causing the SDK to be searched before the
superbuild for libraries which are referred to by a plain `-l` flag in
Fortran-enabled packages. Eventually, NumPy and SciPy end up doing this
and this causes them to be linked against `Accelerate.framework` rather
than the lapack build in the superbuild itself.