This 'awk' source is directly downloaded from the Plan 9 source

http://cm.bell-labs.com/sources/plan9/sys/src/cmd/awk/

as such, it's copyright is held by Lucent Technologies and distributed under the
Lucent Public License version 1.02 [http://www.opensource.org/licenses/lucent1.02.php].

Modifications were made by Jeff Sickel in order to build using Plan 9 from User
Space [http://swtch.com/plan9port/] to the following files:

    mkfile
    re.c