load-foreign

[William.Lott@LISP-PMAX2.SLISP.CS.CMU.EDU]

If Scott wants me to write load-foreign, I also need to redo the C interface.
If I'm going to do that, we should probably talk about the Alien cleanup.

If I remember correctly, you didn't like the way the compiler spent so much
effort trying to assure that pointer dereferences were properly aligned. How
about this:

- alien types become real structures instead of random ``equal'' lists.
- one slot indicates the alignement requirements for that type, if any.
- Make-alien verifies the alignment at creation time iff safety > speed.

This way, alignment only has to be checked at creation time instead of at
every access.

-William