Netscape 4.X does not support the '@import' directive in CSS

stylesheets.  To get around this, append the filename specified in the
'CSS_SHEET_ADDITIONS' variable (if defined) to the end of the default
CSS stylesheet.  This allows us to add document-specific stylesheet
rules while still supporting braindead browsers and reusing the
default CSS code.

share/mk/doc.docbook.mk

@@ -727,4 +727,7 @@ package-${_curformat}: ${PACKAGES}/${.CURDIR:T}.${LANGCODE}.${_curformat}.tgz
 .if ${LOCAL_CSS_SHEET} != ${CSS_SHEET}
 ${LOCAL_CSS_SHEET}: ${CSS_SHEET}
 	${CP} -p ${.ALLSRC} ${.TARGET}
+.if defined(CSS_SHEET_ADDITIONS)
+	${CAT} ${.CURDIR}/${CSS_SHEET_ADDITIONS} >> ${.TARGET}
+.endif
 .endif

share/mk/doc.project.mk

@@ -69,6 +69,7 @@ PREFIX?=	${LOCALBASE}
 PRI_LANG?=	en_US.ISO8859-1
 
 CP?=		/bin/cp
+CAT?=		/bin/cat
 ECHO_CMD?=	echo
 LN?=		/bin/ln
 MKDIR?=		/bin/mkdir -p