Version 2.3.2 is available upstream. Please consider updating! It seems that version 2.3.2 is available upstream, while the latest version in the Gentoo tree is 2.0.3. You think this warning is false? Read more about it here.
suitesparseconfig-7.0.0 fails to build with multilib enabled because of dependencies that cannot be satisfied. All the other packages require it. Bug #908851.
The Block Triangular Form is a library of routines offering
permutation of an unsymmetric matrix (square or rectangular) into
its block upper triangular form (more precisely, it computes a
Dulmage-Mendelsohn decomposition).