Fix most of the warnings generated by compiling lpr with -Wnon-const-format,

Fix most of the warnings generated by compiling lpr with -Wnon-const-format,
often by just telling gcc that some internal routine is "__printflike"
(work done by Kris Kennaway <kris@FreeBSD.org>).  Also fix the new warnings
which show up once gcc starts checking the "printf-like parameters" passed
to those routines.

MFC after:	1 week