liboop: Update.

Signed-off-by: Rudá Moura <ruda.moura@gmail.com>
gmp: Update to version 5.1.3

Signed-off-by: Rudá Moura <ruda.moura@gmail.com>
nettle: Update to version 3.0

Signed-off-by: Rudá Moura <ruda.moura@gmail.com>