As noticed by several users, thorn Formaline had slightly wrong dependencies that would lead to unnecessarily rebuilding all its tarballs under certain circumstances (e.g. when the thorn list changes). I was able to identify the cause, and learned about "order-only prerequisites" in GNU make along the way http://www.gnu.org/software/make/manual/html_node/Prerequisite-Types.html.

This dependency error is now corrected, and Formaline should now rebuild its tarballs only when necessary.

-erik