legacy-cc
The earliest versions of the very first c compiler known to exist in the wild written by the late legend himself dmr.
These are not capable of being compiled today with modern c compilers like gcc. I am only posting these here for the enjoyment and reminiscing of the spark that ignited a soon to be trillion dollar industry. Enjoy. :)
Source: [http://cm.bell-labs.com/cm/cs/who/dmr/primevalC.html]