WIP citrus patch

[Joerg Sonnenberger]

Hi all,
for those of you wondering about the recently added files,
I'm working on integrating the Citrus framework from NetBSD.
The patch at http://leaf.dragonflybsd.org/~joerg/citrus4.diff
is the current stage, but it is *not* final. This needs an
libc major bump, which will be used to clean certain other
parts of libc up too. Consider this mail as FYI if you don't
completely know what you are doing :)

After applying the patch, if you want to test it, remove the
empty files from src/include, otherwise Bad Things Happen(tm).

Joerg