Disable request for both gres/mps and gres/gpu in a single request.
Also disable request for gres/mps and --gpu-freq,
disable mps-per-job with more than 1 node,
disable mps-per-socket with more than 1 socket, and
disable mps-per-task with more than 1 node.
Note these mps-per-* options are not currently available,
but data structures do exist to implement them.

This makes it easier to pass string literals to slurm_perror(3).  For
example, a recent GCC emits the following when a string literal is passed
in C++:

   ISO C++ forbids converting a string constant to 'char*'

Bug 6082

Rework one timer error message while here.

Bug 5861.

Bug 6013

The GRES node information in slurmctld is now as we want it to be.
No job/step scheduling logic implemented yet.

Previous logic was printing a uint64_t as %lld and the test was
looking for a negative number. This corrects the test.

Test was sometimes failing due to delay in getting job accounting
data to database.

Use __func__, collapse message format to a single line as well.

Ensure _GNU_SOURCE is defined. For FreeBSD or NetBSD, define it
as equivalent to POLLHUP up front, rather than the #ifdefs inline.

Remove config.h include, it is not needed here at this point.

Also add plugin name to some logs

Bug 5836.

Wrong author.

This reverts commit e1c10fea.

Bug 5836.

Bug 5836.

Bug 6162

much work still required

Required for gres/mps

Also internally sort GresTypes so that the gres/gpu plugin is processed
before gres/mps. gres/mps will leverage the gres/gpu plugin.

Bug 6163

Backups already run it when dropping to backup.

Bug 6098.

Backups already run it when dropping to backup.

Bug 6098.

Missed from 0d9b7d5d.

Remove the README and point to the web page.

Add details on the disable_x11 option.

Bug 5936.

Also throw an error message within stepd_available() if the nodename
is not set or cannot be inferred correctly.

Bug 5399.

Remove the configuration entry, and update docs to remove it.

There is no option to disable this, as I believe the amended behavior
is expected and safer for all systems.

Bug 5297.

Spelling, suggestions, trailing whitespace.

Bug 6044

No change in logic

Bug 6120