This is a port of the bulk of the Plan 9 software build environment to
Unix.  It 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 and manual pages

  - Plan 9 bitmap fonts

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