Use more precision for bounds, GMP

Hi, I have a problem whose bounds are values which need (really) a lot
of precision.  Much more than double can offer.  I've handled these
values so far with GNU MPFR, which can AFAIK convert to GNU GMP types
which are (?) internally used by GLPK if it's built with support for
that.

Looking through the source I see that the functions to set bounds as
well as the structures (for example struct GLPROW) use double. Thus I
guess I'd need to change that at least ...

Given I have no knowledge (yet?) about the internal complexities of
GLPK ... how hard do you estimate it to be to change GLPK to allow
bounds set from GMP numbers?

Best regards,
Daniel