also return -1 in more failure cases

Bug 5815

Coverity CID 188689

Also simplify this xstrfmtcat() into an xstrcat() call while here.

Bug 5828.

This fixes some problems with job steps that allocate subsets of
the job's GRES allocation.

add logic so that a job step can be allocated subsets of the job's
GRES allocation, even when the GRES specifications differ. For example,
the job can specifiy gres-per-node and the step gres-per-task.

Update slurm.spec and slurm.spec-legacy as well.

Update slurm.spec and slurm.spec-legacy as well.

Bug 5479

Bug 5553

Bug 5744

Bug 5476.

SLURM_FAILURE removed in a76a9486.

Leads to false-positive warnings about settings being too low when
they're actually fine. E.g., if innodb_buffer_pool_size is over 2GB
the warning would have been printed in error.

Bug 5661.

Bug 5594.