Unused code

[Torbjorn Granlund]

I'd like to locate unused code in GMP.

Unused code adds size to the source, which is not too bad, but if it is
compiled, it adds size to the compiled library, in particular to the
shared library (which is always mapped in its entire when a process
linked to it is running).

My current list is short:
  toom62
  toom54

Are you aware if any more files or functions that are unused?

I think we should disable compilation of unused functions, and if we
don't expect them to ever be used, also remove their sources.

-- 
Torbjörn