This version has a step debugger, which now completely replaces the
old trace feature. Also, we moved all of the FreeBSD-specific MI
code to loader.c, reducing the diff between this and the official
FICL distribution.
Also, export the file_findfile() function. Again, this is taken from
work in progress but frozen for the time being. Since it works, I'd
rather commit and remove any uglyness later than hide it on my tree.
