(the job number, given jp a pointer to a jobs table entry)
used open coded previously in many places (mostly in DEBUG mode
trace messages, so not included in most shells, but there are
a few others).
Make the type of JNUM() be int rather than the ptrdiff_t the
open coded version became ... which when used in some printf()
type function arg list was cast to some other arbitrary (but not
consistent) int type for which there is a standard %Xd type
format conversion. Now we can (and do) just use %d for this.
If the number of jobs ever exceeds the range of an int, we would
have far more serious problems than the broken output this would
cause.
While here improve a comment or two, and use JOBRUNNING instead
of 0 where the intent is the former (JOBRUNNING is #defined as 0).
NFCI.
21f0086877