Log Message:
Changes 5.1.3:

  BUGS FIXED
  * The internal functions mpn_sbpi1_div_qr_sec mpn_sbpi1_div_r_sec could
    compute garbage with a low probability.  They are now rewritten, and the
    test code has been improved.

  * A bug in the ia64 implementation of mpn_divrem_2, clobbering some
    callee-save registers, has been fixed. This is an internal
    function, with the bug manifesting itself as miscomputation in,
    e.g., mpn_sqrtrem.

  * The documentation now correctly says 'const' for input arguments.