For the impatient:
tackon.dll is a plugin for NSIS, the scriptable Windows installer from Nullsoft. It allows you to “tack on” and later retrieve an arbitrary amount of data from an NSIS installer package.
Tackon was written by the developers of Blogtorrent, a Downhill Battle project. Tackon is distributed as part of the Blogtorrent source code.
A mingw Makefile is provided for building tackon, but installing mingw on Windows can be downright painful. Even installing on Linux takes a little effort. So, I’m hosting the tackon.dll binary here for those who’d like to hack on NSIS and/or Blogtorrent, but would like to skip the hassle of building tackon themselves.