The -Wno-unused-result option looks to have been introduced in GCC 4.5.0.
So it's need turn off FORTIFY_SOURCE (compiler warn about unused results
in fortification mode) instead of use -Wno-unused-result to avoid error
in versions prior to 4.5.0.
Signed-off-by: Victor Konyashkin  <vkonyashkin@parallels.com>
Acked-by: Andrey Wagin <avagin@openvz.org>
Signed-off-by: Pavel Emelyanov <xemul@parallels.com>