Installing from scratch is not working for HEAD.
It drops this error:
Fatal error: Cannot redeclare print_object() (previously declared in /Users/stronk7/cvs_moodle/moodle_head/install.php:700) in /Users/stronk7/cvs_moodle/moodle_head/lib/datalib.php on line 1549
Somewhere datalib.php is being included, while it wasn't in 1.7
Solution: Delete print_object() from install ? Although I think it should be any good reason preventing datalib.php to be included by install.php in the past.
This is IMPORTANT to fix ASAP. Marked as blocker.