We've decided to use the same convention as the Linux kernel folks for version numbering, where the version is given as major .minor.bugfix. The minor number will be an even number for a stable production release; an odd minor number will be used for development or experimental releases that should not be used in releases of products to end users.
ZooLib's first public release version number is 0.8.1. Subject to the disclaimer given in the ZooLib License this version should be considered production code, suitable for use in end-user programs when used on the Mac OS or Windows platforms. The BeOS implementation appears to be fully functional but has not been extensively tested nor have products been built out of the BeOS version that have been in actual use in the field. The Posix implementation is incomplete; it lacks a menu bar widget and an implementation of resource files as discussed in What ZooLib Needs for the Future.
All platforms really need some kind of Unicode implementation to be able to handle text with diacritics in a cross-platform way, or non-latin text, especially multibyte character sets.
The ZooLib source code is provided in several archive formats to make it easier for you to unpack. In each case the source code itself is kept in Unix newline-style text format, which appears to work across most compilers.
Be aware that corrupting the text file format of a makefile appears to break GNU make - this appears to happen if you archive a text file with Stuffit on the Mac OS and unpack it with Aladdin Expander on Windows; there is no option in Expander to avoid translating text files.
To build the code, download the sample source code and use the makefiles or the CodeWarrior projects in there as a starting point. Be sure to read the build instructions.