Aocl

AMD Optimizing CPU Libraries, whose BLAS is BLIS with the CBLAS interface compiled in.

The serial build comes first. AOCL ships BLIS twice, once linked against a threading runtime and once without, and both are held to one compute thread here; taking the serial build means the single-thread requirement is met by the binary rather than by a call that configures a pool down to one. The multithreaded build stays a candidate because a host may have only that one installed, and it is still correct, just configured rather than built that way.

Two sonames, because two projects package this library. AMD's AOCL 5 carries libblis.so.5; a distribution's own BLIS package is a release behind at libblis.so.4.