upstream_svn_uri = svn://flashrom.org/flashrom/trunk
upstream_svn_rev = $$(printf '%s\n' '$(OPK_SOURCE_VERSION_UPSTREAM)' | \
	sed 's/^.*[~+]r\([0-9][0-9]*\).*$$/\1/')
source_archive = ../$(OPK_SOURCE)-$(OPK_SOURCE_VERSION_UPSTREAM).orig.tar.bz2

$(source_archive):
	svn export -r "$(upstream_svn_rev)" "$(upstream_svn_uri)" \
		'$(OPK_SOURCE)'
	tar -cjf '$(@)' '$(OPK_SOURCE)'
	rm -Rf src
	mv '$(OPK_SOURCE)' src

source: $(source_archive)