I see only one problem: AFAIR the GNU install-info has to be minimal and
    cannot rely on (many) other things. 
Yes, GNU I-I can't rely on much of anything else.  Probably best for it
to stay a C program.
As I understand it, the wrapper would be in debian only, not gnu.  Works
for me.  Probably nicer than the optional-number-of-arguments-in-getopt
stuff.
Thanks,
k