gmp

[Henry Cejtin]

re compiling gmp for the machine you are running on, this is the big argument
in favor of using shared libraries.  The big disadvantage is that  then  your
program won't work at all on machines that don't have any copy of gmp.

My  general  feeling  is that the gmp people are a bit crazy about efficiency
and that the cost of NOT optimizing for your particular CPU isn't that great.
This feeling is on the basis of no tests, just a general impression.