ZooLib allows one to write a single set of C++ sources which can be compiled into native executables for Mac OS, Windows, BeOS, or POSIX-compliant systems that use the X Window system (such as Linux). Zoolib provides a GUI toolkit with a uniquely flexible layout system. It also provides a single-file database format, TCP networking, and extensive debugging support. ZooLib applications are multithreaded. ZooLib requires only minimal support from the underlying OS and platform GUI layer, and thus could be ported to a completely new platform without too much difficulty. ZooLib is fully production quality on Windows and MacOS, completely implemented but untested on BeOS, and not yet complete on POSIX. Please note that the sources from the "demo" branch are also required to build ZooLib or to get started writing your own ZooLib applications.
Slackware is now GLibC2 based
Note the above comments are a couple of years old, Slackware (now at version 8.0) has been glibc2 based for a couple of releases.
Linux Kernel Database Proposed to Make this Easier
One thing that can speed both the development of new kernels, and their adoption when they are released is more widespread and more effective quality assurance of the kernels during development and immediately after released.
The distros often maintain full-time staff to do QA, their resources are necessarily limited. There is no way any company can maintain staff and enough different machines to reproduce all the configurations a new kernel will be used on in production once released.
To encourage more regular users to participate in Linux kernel testing, and to make the process of getting their feedback easier on them, I have proposed the Linux Quality Database
that will provide a web form backed by a powerful database for capturing configuration information and making bugs easily searchable by kernel developers.
It is a big project, and I need help before I can start, particularly from a database architect who can advise me on the schema for the database.
In the meantime, there are articles (http://linuxquality.sunsite.dk/articles/) being placed on the site to guide you in the process of testing the kernel and writing better free software in general.