The code and Makefile are structured so as to generate code that

(1) contains exactly the subroutines needed for each j command
    (to reduce Perl interpretation time)

(2) use our subroutines vs. equivalent system()
    (former is faster).

There's probably a simpler way to do all this, but this wasn't too
bad.


Could extend this idea to jr_rmic, but am keeping that separate for
now at least.

Note: u_init needs to be first alphabetically among those that use the
global variables it defines.  (Could really ensure that by moving
globals to u_aaaaaa or somesuch...)
