build: Add NX workaround for RV64
build: Add NX workaround for RV64

Work around https://bugs.launchpad.net/ubuntu/+source/gcc-8-cross-ports/+bug/1853740.


Former-commit-id: d563b8864d44c972a32af999f205afd673448825
syscoin/syscoin,syscoin/syscoin2,syscoin/syscoin,syscoin/syscoin2,syscoin/syscoin,syscoin/syscoin2,syscoin/syscoin,syscoin/syscoin2,syscoin/syscoin,syscoin/syscoin,syscoin/syscoin,syscoin/syscoin2,syscoin/syscoin2,syscoin/syscoin