upstream_base_name = $(upstream_source)-$(OPK_SOURCE_VERSION_UPSTREAM)
upstream_dir = http://ftp.gnome.org/pub/gnome/sources/$(upstream_source)
upstream_base_ver = $$(printf '%s\n' '$(OPK_SOURCE_VERSION_UPSTREAM)' | \
	sed 's/^\([0-9]*\.[0-9]*\)\..*$$/\1/')
upstream_base_url = $(upstream_dir)/$(upstream_base_ver)/$(upstream_base_name)
source_archive = ../$(OPK_SOURCE)-$(OPK_SOURCE_VERSION_UPSTREAM).orig.tar.gz

$(source_archive):
	wget -c "$(upstream_base_url).tar.xz"
	wget -O - "$(upstream_base_url).sha256sum" | grep -F .tar.xz >sha256sum
	sha256sum -c sha256sum
	rm sha256sum
	unxz -c '$(upstream_base_name).tar.xz' | tar -x
	tar -czf '$(source_archive)' $(upstream_source)-*/
	mv $(upstream_source)-*/ src/

source: $(source_archive)