addresses problem reported by clang

bug introduced in commit a7d9313d

When a job with time_end=0 and TRES null exists from an association that is
currently inside a reservation, the hourly rollup segfaults.

Bug 5143

And from underlying slurm_msg_sendto_timeout call as well.

Add function to clear total_gres at start of scheduling cycle
Modify logic to avoid overflow on gpu counter

As reported by Avalon Johnson on slurm-users
https://groups.google.com/forum/#!topic/slurm-users/BsMQ7Uk1PLw
Bug 5287.

bug 4373, comment #24

Removed the sentence which incorrectly stated that when not using the
gres flag enforce-binding option, cpus other than the ones defined in gres.conf
could be used for a gpu.

Bug 5189

srun was already fixed in b7053bda (Bug 3294).

Bug 5126

bug 5189

Add salloc/sbatch/srun option of --gres-flags=disable-binding to disable
    filtering of CPUs with respect to generic resource locality. This option is
    currently required to use more CPUs than are bound to a GRES (i.e. if a GPU
    is bound to the CPUs on one socket, but resources on more than one socket
    are required to run the job). This option may permit a job to be allocated
    resources sooner than otherwise possible, but may result in lower job
    performance.
bug 5189

'have_innodb' is deprecated.

Bug 5317.

Cleanup printf formaters and ensure they match the types:
%zu for size_t
%zd for ssize_t

Bug 5417.

When printing arrays in squeue and setting the SLURM_BITSTR_LEN variable to 0
or to NULL, the length of the output defaulted to 64, when the documentation
says it will default to "unlimited". This patch fixes this situation.

Bug 5440

Because of a bug in the some versions of the Linux kernel, disable
constraining kernel memory space with cgroups by default.

Bug 5223.

Coverity CID 186991

Logic was switched around in 17.11, enable_user_top is now the
correct option.

Bug 5165.

This is not working reliably even when setting
SchedulerParameters=enable_hetero_steps and/or using OpenMPI with Slurm's
mpi/pmi2, as it was previously documented.

Bug 5309.

Bug 5426.

Bug 5426.

Bug 5426.

Bug 5426.

Still needs some work here. Ideally the length of the
script should be read out of the msg struct, rather
than recomputed. That would also move us closer to allowing
binary data in the script.

As we already copy this on the normal path out of here,
just use a heap allocation to begin with.

Sync error messages between _log_init and _sched_log_init.

Add _GNU_SOURCE define to expose O_CLOEXEC on older platforms.