Name     License    Description
===============================================================================
libql    LGPLv3+    Small, fast coroutines library for C.

For more information on coroutines, see: http://en.wikipedia.org/wiki/Coroutine

I have currently tested libql's engines on:

         | setjmp  | ucontext | pthread |
===============================================================================
Debian   | YES [1] |   YES    |   YES   |
Fedora   | YES [1] |   YES    |   YES   |
FreeBSD  | YES [1] |   YES    |   YES   |
NetBSD   | YES [1] |    NO    |   YES   |
OpenBSD  | YES [1] |   YES    |   YES   |
MacOSX   | YES [1] |    NO    |   YES   |
Windows  | YES [2] |    NO    |    NO   |
Solaris  | YES [1] |   YES    |   YES   |

1 - i386, x86_64, ARM and MIPS
2 - Currently i386-only, patches welcome