Merge branch 'maint-0.2.9' into maint-0.3.0

  o Minor bugfixes (compilation):

    - Fix unused variable warnings in donna's Curve25519 SSE2 code.

      Fixes bug 22895; bugfix on 0.2.7.2-alpha.

typedef packedelem64 packed64bignum25519[10];

static const packedelem32 bot32bitmask = {{0xffffffff, 0x00000000, 0xffffffff, 0x00000000}};

static const packedelem32 top32bitmask = {{0x00000000, 0xffffffff, 0x00000000, 0xffffffff}};

static const packedelem32 top64bitmask = {{0x00000000, 0x00000000, 0xffffffff, 0xffffffff}};

static const packedelem32 bot64bitmask = {{0xffffffff, 0xffffffff, 0x00000000, 0x00000000}};

/* reduction masks */

static const packedelem64 packedmask26 = {{0x03ffffff, 0x03ffffff}};

static const packedelem64 packedmask25 = {{0x01ffffff, 0x01ffffff}};

static const packedelem32 packedmask2625 = {{0x3ffffff,0,0x1ffffff,0}};

static const packedelem32 packedmask26262626 = {{0x03ffffff, 0x03ffffff, 0x03ffffff, 0x03ffffff}};

static const packedelem32 packedmask25252525 = {{0x01ffffff, 0x01ffffff, 0x01ffffff, 0x01ffffff}};

/* multipliers */

static const packedelem64 packednineteen = {{19, 19}};

static const packedelem64 packednineteenone = {{19, 1}};

static const packedelem64 packedthirtyeight = {{38, 38}};

static const packedelem64 packed3819 = {{19*2,19}};

static const packedelem64 packed9638 = {{19*4,19*2}};

/* 121666,121665 */

static const packedelem64 packed121666121665 = {{121666, 121665}};

/* 2*(2^255 - 19) = 0 mod p */

static const packedelem32 packed2p0 = {{0x7ffffda,0x3fffffe,0x7fffffe,0x3fffffe}};