gmp: move BBCLASSEXTEND = "native nativesdk" from gmp.inc into 6.1.0 recipe
It's unlikely that native builds of gmp 4.2.1 (ie the last LGPLv2
version) would ever be required (and given that recent versions of gcc
require gmp >= 4.3.2, native builds of gmp 4.2.1 are unlikely to work
very well). Restrict native and nativesdk builds to gmp 6.1.0 only.
https://gcc.gnu.org/install/prerequisites.html
Signed-off-by: Andre McCurdy <armccurdy@gmail.com> Signed-off-by: Ross Burton <ross.burton@intel.com>
