It appears that building GHC requires Happy. It appears that building Happy requires GHC. How does one bootstrap this thing ?

Building GHC shouldn't really require Happy, but there's a bug in the 5.02 source distribution which means that the configure script complains if you don't have Happy installed. Hacking the configure script to remove the check will get you going. (as Simon said you still need GHC, though). Cheers, Simon