make flags:    
building meta-build
sed "s@__prefix__@/nix/store/2k9a18lhk31zlhk1bk62wilvl8flx6qn-meta-build-env@g;\
	     s@__datadir__@/nix/store/2k9a18lhk31zlhk1bk62wilvl8flx6qn-meta-build-env/share@g;\
	     s@__PACKAGE__@meta-build-env@g" < meta-build.src > meta-build && chmod +x meta-build