calls never block) This is only used in slurmd/mgr.c right now,
   so that log functions called in io.c do not deadlock IO thread.
 o cleanup in srun/srun.c

 o slurmd: if there is room in cmdline, change argv to show
   what job a slurmd is managing.

   support documented uses of --input,output,error)
 o Allow premature termination of srun (i.e. when IO is not yet
   complete) by insistent user.
 o added xstrfmtcat() and xmemcat() to xstring.c