Free portable software for linux

RSS Viewer is a comfortable and portable viewer for RSS/RDF-compatible newsfeeds. It is written completely in Java and licensed under the GNU General Public License.
Rss Viewer is proven to run on Windows, Linux and MacOS X. Other Java enabled platforms should work as well.
Main features:
- multiple views for everyones taste
- built-in HTML article preview
- external browser support
- drag and drop
- article database

thttpd is a simple, small, portable, fast, and secure HTTP server:
Simple; It handles only the minimum necessary to implement HTTP/1.1. Well, maybe a little more than the minimum.
Small; See the comparison chart. It also has a very small run-time size, since it does not fork and is very careful about memory allocation.
Portable; It compiles cleanly on most any Unix-like OS, specifically including FreeBSD, SunOS 4, Solaris 2, BSD/OS, Linux, OSF.
Fast; In typical use its about as fast as the best full-featured servers (Apache, NCSA, Netscape). Under extreme load its much faster.
Secure; It goes to great lengths to protect the web server machine against attacks and breakins from other sites.
It also has one extremely useful feature (URL-traffic-based throttling) that no other server currently has. Plus, it supports IPv6 out of the box, no patching required.
Enhancements:
- Move fdwatch initialization before the chroot, so that /dev/poll can work.
- Multiple fdwatch cleanups and fixes (Adam Zell).

Portable Coroutine Library (PCL) implements the low level functionality for coroutines. For a definition of the term coroutine see The Art of Computer Programming by Donald E. Knuth.
Coroutines are a very simple cooperative multitasking environment where the switch from one task to another is done explicitly by a function call. Coroutines are a lot faster than processes or threads switch, since there is no OS kernel involvement for the operation.
Also coroutines require much less OS resources than processes of threads. The idea of writing this library started when I was testing Linux epoll functionality and performance.
I initially started using the coro library by E. Toernig and I found the library very interesting. It was simple and yet powerful. The limitations of the coro library were both non portability and crashes when not used together with certain versions of gcc.
So I decided to write a new library to address the problems aforementioned by also taking portable context switching ideas from the GNU Pth library. This library is easily portable on almost every Unix system and on Windows.
It can use either the ucontext.h functionalities ( getcontext()/makecontest()/swapcontext() ) or the standard longjmp()/setjmp().
Enhancements:
- This release fixes a shared library soname generation error that was missing the library version information.

libdnet provides a simplified, portable interface to several low-level networking routines.
Main features:
- network address manipulation
- kernel arp(4) cache and route(4) table lookup and manipulation
- network firewalling (IP filter, ipfw, ipchains, pf, PktFilter, ...)
- network interface lookup and manipulation
- IP tunnelling (BSD/Linux tun, Universal TUN/TAP device)
- raw IP packet and Ethernet frame transmission
Supported languages:
- C, C++
- Python
- Perl, Ruby (see below)
Supported platforms:
- BSD (OpenBSD, FreeBSD, NetBSD, BSD/OS)
- Linux (Redhat, Debian, Slackware, etc.)
- MacOS X
- Windows (NT/2000/XP)
- Solaris
- IRIX
- HP-UX
- Tru64

GLEW (OpenGL Extension Wrangler Library) is a simple tool that helps C/C++ developers initialize extensions and write portable applications.

GLEW currently supports a variety of operating systems, including Windows, Linux, Darwin, Irix, and Solaris.

fontimage project is a small, portable tool that generates PNG images of text strings directly from outline font files.
Main features:
- only depnends on libpng and freetype, should be very portable
- handles charaters outside of ascii range
- Licensed under GNU GPL
- Tested on Fedora Core 5 and CentOS 4.3