HELP SYS_GRBG_DESTLIST                          Steve Knight, 16 Oct 91

    sys_grbg_destlist( <expanded list> ) -> A1, ..., AN, N

For experts only!

Explodes an expanded list into a counted group and returns all the pairs
of the spine of the list to the pairs-freelist.  

Misuse of this procedure will crash Poplog!