[Hat] OS 10.5

The news is both good and bad when trying to run Hat on OS X 10.5... The bad: • The ghcsym bug appears to have returned. The good: • Readline is there by default, so nice stuff happens in hat-observe, and the make file glitch doesn't bite. • Other than the ghcsym bug, the compile went through smoothly first time, that's a new one for OS X! Bob