This is a port of the bulk of the Plan 9 software build environment to
Unix.

This port tries to reproduce the Plan 9 build environment as faithfully
as possible, providing u.h and libc.h, and blithely redefining tokens
such as open, dup, and accept in order to provide implementations that
better mimic the Plan 9 semantics. The result is a more complicated and
less Unix-friendly environment, but Plan 9 programs can typically be
compiled with little or no changes.

The port includes the following:

sources for Linux, FreeBSD, and SunOS

lib9 (nee libc), libString, libbin, libbio, libcomplete, libdraw,
liblibflate, frame, libfs, libhtml, libhttpd, libip, libmux, libplumb,
liblibregexp, libsec, thread, and libventi

9term, acme, hoc, plumber, rio (nee 9wm), sam, and samterm, along with
many small utilities
Plan 9 bitmap fonts
manual pages

WWW: http://swtch.com/plan9port/