ITS#9520 Refuse parallelism if not compiled with libargon2

3 jobs for master in 46 minutes and 17 seconds (queued for 1 second)
Status Name Job ID Coverage
  Build
passed build-gnutls-mit-standalone-lloadd #6451

00:44:37

passed build-no-threads-no-slapd #6449

00:02:46

passed build-openssl-heimdal-lloadd #6450

00:46:17