Provide some vars for use in template's targets.

These new vars are DESTDIR (by default XBPS_DESTDIR/pkgname-version),
SRCPKGDESTDIR (XBPS_DESTDIR/sourcepkg-version) and FILESDIR
(XBPS_TEMPLATESDIR/pkgname/files).

This simplifies packages that used them.

--HG--
extra : convert_revision : 287ea7128cb5df19870ca7aff0a3b8f99a11d63a

templates/xbps-base-pkg/template

@@ -14,13 +14,11 @@ Add_dependency run proplib
 
 do_install()
 {
-	local destdir=$XBPS_DESTDIR/$pkgname-$version
-
-	mkdir -p ${destdir}/lib
+	mkdir -p ${DESTDIR}/lib
 
 	for f in bin cmpver digest repo pkgdb; do
 		install -D -m755 /usr/local/sbin/xbps-${f} \
-			${destdir}/sbin/xbps-${f}
+			${DESTDIR}/sbin/xbps-${f}
 	done
-	cp -a /usr/local/lib/libxbps.so* ${destdir}/lib
+	cp -a /usr/local/lib/libxbps.so* ${DESTDIR}/lib
 }