Paginate and print buffer contents.
The variable `lpr-headers-switches' controls how to paginate.
If it is nil (the default), we run the `pr' program (or whatever program
`lpr-page-header-program' specifies) to paginate.
`lpr-page-header-switches' specifies the switches for that program.
Otherwise, the switches in `lpr-headers-switches' are used
in the print command itself; we expect them to request pagination.
See the variables `lpr-switches' and `lpr-command'
for further customization of the printer command. (fn)