20240622
  solvers2.tgz:  fix various more bugs related to parallel
evaluations.  New int asl->P.thusedsetup records the number of threads
used in the last call on sphes_setup (which is called automatically if
needed and not yet called).  This joins asl->P.thused for the number
of threads used in the most recent sphes call and asl->P.thusedhv for
the number of threads used in the most recent Hessian-vector product.
These numbers can be requested to be printed when they change by
setting bits 16, 32, or 64 of asl->P.sphopts for setup, sphes, and
(for 64) the various Hessian-vector product functions.