#1901 / macOS: better err msg on proc_pidinfo()
#1901 / macOS: better err msg on proc_pidinfo()

Signed-off-by: Giampaolo Rodola <a87591e89a990e1a9e66d5a1def1da90515f45ba@gmail.com>

giampaolo/psutil,0-wiz-0/psutil,giampaolo/psutil,0-wiz-0/psutil