s some tedium but is otherwise perhaps not too important.
     Currently <code>mpz_set_f</code> and <code>mpf_cmp_ui</code> depend on
     exp==0, maybe elsewhere too.
<li> <code>__gmp_allocate_func</code>: Could use GCC <code>__attribute__
     ((malloc))</code> on this, though don't know if it'd do much.  GCC 3.0
     allows that attribute on functions, but not function pointers (see info
     node "Attribute Syntax"), so would need a new autoconf test.  This can
     wait until there's a GCC that support