When building release documentation for release builds or for

release documentation snapshots, force URLS_ABSOLUTE.  This
allows us to relocate HTML renderings anywhere without worrying
about breaking relative links to pages on the Web site.  This can
happen when we use &base; as part of a URL.

I wonder if we should do this for all release documentation builds,
but I'm not quite sure what all the cases are.

release/Makefile

@@ -1014,7 +1014,7 @@ doc.1:
 doc.2:
 	@echo "Making release documentation..."
 	@cd ${.CURDIR}/doc && make all install clean 'FORMATS=html txt' \
-	    INSTALL_COMPRESSED='' DOCDIR=${RND}
+	    INSTALL_COMPRESSED='' URLS_ABSOLUTE=YES DOCDIR=${RND}
 	touch ${.TARGET}
 
 # Various "subroutine" and other supporting targets.

release/doc/share/examples/Makefile.relnotesng

@@ -20,7 +20,7 @@ DOC_PREFIX?=	/usr/doc
 CSS_SHEET?=	${DOC_PREFIX}/share/misc/docbook.css
 FORMATS?=	html txt pdf
 
-BUILD_OPTIONS?=
+BUILD_OPTIONS+=	URLS_ABSOLUTE=YES
 
 all:
 	(cd ${DOCDIR}; ${MAKE} DOC_PREFIX=${DOC_PREFIX} FORMATS="${FORMATS}" ${BUILD_OPTIONS} all)