upstream_base_url = http://downloads.xiph.org/releases/$(upstream_source_dir)
upstream_url = $(upstream_base_url)/$(upstream_archive)
upstream_archive = $(OPK_SOURCE)-$(OPK_SOURCE_VERSION_UPSTREAM).tar.gz
source_archive = ../$(OPK_SOURCE)-$(OPK_SOURCE_VERSION_UPSTREAM).orig.tar.gz

$(source_archive):
	wget -c '$(upstream_url)'
	printf '$(source_md5sum)  $(upstream_archive)' | md5sum -c -
	mv '$(upstream_archive)' '$(source_archive)'

source: $(source_archive)