See http://www.amnoid.de/icns/makeicns.html for original code of makeicns (version 1.1 as of 2010-05-01) which seems to be abandoned at the moment.
A more recent version of IconFamily (http://sourceforge.net/projects/iconfamily/) is being used to avoid many deprecation-warnings during build (version 0.9.4 as of 2010-05-01).
The tool has been extended a little bit:
- non-square images are not stretched anymore and can be (left, right, top, bottom, center) aligned in the icns output file
- error message on non-existent input files