current state, it can handle all but four of the 991 zip files (including
jar files) I was able to identify in the ports tree. The remaining four
are two self-extracting archives and two which have garbage preceding the
first local header. This limitation is a feature of libarchive(3) which
I am currently working to resolve.
The code is unnecessarily large due to the need to emulate the exact
command-line syntax and behaviour of ports/unzip. My initial incompatible
implementation was one quarter the size of the one I am committing here.
