This port installs the module KLU of SuiteSparse.

KLU is a set of routines for solving sparse linear systems of equations. It is
particularly well-suited to matrices arising in SPICE-like circuit simulation
applications. It relies on a permutation to block triangular form (BTF), several
methods for finding a fill-reducing ordering (variants of approximate minimum
degree, and nested dissection), and a sparse left-looking LU factorization
method to factorize each block.