 is not always available (it's in
     C99 and GCC though), disadvantages of using <code>long long</code> in
     libgmp.a would be
     <ul>
     <li> Library contents vary according to the build compiler.
     <li> gmp.h would need an ugly <code>#ifdef</code> block to decide if the
          application compiler could take the <code>long long</code>
          prototypes.
     <li> Some sort of <code>LIBGMP_HAS_LONGLONG</code> might be wanted to
          indicate whether the functions are available.  (App