Don't pass -o1- to groff(1) by default. If ms(7) formatted document

uses the .RP macro, a separate cover page is created as page 0 which
is not otherwise output.  The bug was hiding by a hack in troffrc
that disables SGR support in grotty(1), which I'm going to remove now.
For POLA reasons, still disable SGR support in grotty(1), by passing
-P-c to groff(1).  If we want SGR sequences in these documents, this
can be removed.

MFC after:	1 week

share/mk/bsd.doc.mk

@@ -54,10 +54,10 @@ INDXBIB?=	indxbib
 PIC?=		pic
 REFER?=		refer
 .for _dev in ${PRINTERDEVICE:Mascii}
-ROFF.ascii?=	groff -Tascii ${TRFLAGS} -mtty-char ${MACROS} -o${PAGES}
+ROFF.ascii?=	groff -Tascii -P-c ${TRFLAGS} -mtty-char ${MACROS} ${PAGES:C/^/-o/1}
 .endfor
 .for _dev in ${PRINTERDEVICE:Nascii}
-ROFF.${_dev}?=	groff -T${_dev} ${TRFLAGS} ${MACROS} -o${PAGES}
+ROFF.${_dev}?=	groff -T${_dev} ${TRFLAGS} ${MACROS} ${PAGES:C/^/-o/1}
 .endfor
 SOELIM?=	soelim
 TBL?=		tbl
@@ -94,8 +94,6 @@ DFILE.${_dev}=	${DOC}.${_dev}${DCOMPRESS_EXT}
 .endif
 .endfor
 
-PAGES?=		1-
-
 UNROFF?=	unroff
 HTML_SPLIT?=	yes
 UNROFFFLAGS?=	-fhtml