scotch5 5.1.12b: New formula
scotch5 5.1.12b: New formula

a library for (hyper)graph partitioning
This is the latest version of the v5 series. The new version 6 has
introduced some API incompatibilities and a few programs hence need
this older version.

Closes #294

kozo2/homebrew-science,aeantipov/homebrew-science,maplesond/homebrew-science,ahundt/homebrew-science,philippbayer/homebrew-science,goxberry/homebrew-science,pmelsted/homebrew-science,quantumsteve/homebrew-science,dpo/homebrew-science,heuermh/homebrew-science,andrewjpage/homebrew-science,DabeDotCom/homebrew-science,parcollet/homebrew-science,pditommaso/homebrew-science,ge11232002/homebrew-science,joshbode/homebrew-science