Replacement for GMP: Update

[Peter Tanski]

Simon PJ and Bulat,

> [the] ForeignPtr
> solution [has] gotten a lot cheaper in GHC 6.6 than it used to be, so
> it's worth trying.  A merit of the approach is that is avoids fiddling
> with the bignum allocator at all.

I actually did not know that until today; I have tried to keep up  
with the rapid changes going on but until Simon Marlow posted the FFI  
syntax patch on cvs-ghc-request I had not read into it that much.  It  
won't be too much trouble for me to do a bare FFI binding to GMP or  
another library (people seem to be having problems with OpenSSL's  
license) but what I have been doing still applies: writing bitwise  
operators and cleaning things up.  I don't know how much the  
indirection of a FFI binding would degrade the speed compared to a  
direct C-- binding (you have an extra function call with FFI); it  
should not be any more costly than indirection through two pointers.   
This will be quick: I will set up a GMP-FFI binding as a speed- 
reference, for starters.

Best regards,
Peter