Using the delivered mk to rebuild mk.

You should be able to use the delivered executable of mk to
build a new executable.  This may be of particular interest
on Windows NT/Win95 where the path of the shell program
can be hard-coded by changing the variable named "shell"
near the beginning of source file Nt.c.

Mk uses the regular expression library, so build
the program as follows:

1.  ensure that ../../mkconfig contains the proper system definitions

2.  ensure that the system libraries lib9, libbio, and libregexp have
	been built.  you can do this by hand by changing to ../lib9,
	../libbio, and ../libregexp and doing "mk nuke" and a "mk install"
	in each.

3. in this directory
	mk nuke
	mk install

4. on NT/Win95 the executable must be installed by hand because the current
	executable is locked down while it is executing:

	mv obj.out ../../Nt/386/bin/mk.exe
