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/gcc/objc++.template

@@ -12,8 +12,6 @@ Add_dependency run gcc-objc
 
 do_install()
 {
-	local destdir=${XBPS_DESTDIR}/${pkgname}-${version}
-	local origdir=${XBPS_DESTDIR}/${sourcepkg}-${version}
 	local triplet=
 
 	if [ "${xbps_machine}" = "x86_64" ]; then
@@ -22,7 +20,7 @@ do_install()
 		triplet="${xbps_machine}-pc-linux-gnu"
 	fi
 
-	mkdir -p ${destdir}/usr/libexec/gcc/${triplet}/${version}
-	mv ${origdir}/usr/libexec/gcc/${triplet}/${version}/cc1objplus \
-		${destdir}/usr/libexec/gcc/${triplet}/${version}
+	mkdir -p ${DESTDIR}/usr/libexec/gcc/${triplet}/${version}
+	mv ${SRCPKGDESTDIR}/usr/libexec/gcc/${triplet}/${version}/cc1objplus \
+		${DESTDIR}/usr/libexec/gcc/${triplet}/${version}
 }