Syncing xen.org pv-grub up to commit 87a05a4:

commit 87a05a45860d93455e4cf5672c2b8566c090fb44
Author: Olaf Hering <olaf@aepfle.de>
Date:   Thu Oct 18 09:34:59 2012 +0100

    stubdom: fix compile errors in grub

    Building xen.rpm in SLES11 started to fail due to these compiler
    warnings:

    [ 1436s] ../grub-upstream/netboot/fsys_tftp.c:213: warning: operation on 'block' may be undefined
    [ 1437s] ../grub-upstream/netboot/main.c:444: warning: operation on 'block' may be undefined

    [ 1234s] E: xen sequence-point ../grub-upstream/netboot/fsys_tftp.c:213
    [ 1234s] E: xen sequence-point ../grub-upstream/netboot/main.c:444

    The reason for this is that the assignment is done twice:
     tp.u.ack.block = ((uint16_t)( (((uint16_t)((block = prevblock)) & (uint16_t)0x00ffU) << 8) | (((uint16_t)((block = prevblock)) & (uint16_t)0xff00U) >> 8)));

    Fix this package build error by adding another patch for grub, which
    moves the assignment out of the macro usage.

    Signed-off-by: Olaf Hering <olaf@aepfle.de>
    Acked-by: Ian Campbell <ian.campbell@citrix.com>
    Committed-by: Ian Campbell <ian.campbell@citrix.com>