[project @ 2001-03-19 16:22:00 by simonmar]

[project @ 2001-03-19 16:22:00 by simonmar]
Fix a problem with the 'it' variable in GHCi.  New bindings for 'it'
were getting confused with old bindings, because we always used the
same 'it' name.

Now, we generate a new unique for 'it' each time around.

Also, make sure that any existing variables shadowed by new
command-line bindings are correctly removed from the environments to
avoid space leaks.