library: tweak 'other' user/group names for efficiency

library: tweak 'other' user/group names for efficiency

This commit just ensures that the relatively expensive
ID to name conversions aren't performed unless they're
explicitly requested. It also internalizes those flags
that required the PROC_FILLSTATUS flag to also be set.

[ requiring a caller, in our case pids.c, to provide ]
[ two flags when a single field was the objective is ]
[ wrong & represents a future potential toe-stubber. ]

[ moreover, what's worse is that those two flags are ]
[ seemingly unrelated. but, without both, a SEGV can ]
[ can be expected when a result.str pointer is NULL. ]

[ by contrast, in the master branch those fields are ]
[ arrays which, when set to zeroes, produce an empty ]
[ string. So, there is no abend (but no name either) ]
[ when one of those two required flags were omitted. ]

[ and worth noting, in that branch it's not just one ]
[ caller required to observe a two flag requirement. ]

Signed-off-by: Jim Warner <james.warner@comcast.net>