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: 0539bcb35723eec4c1d689d8ea5488b8415ecafc
syscoin/syscoin,syscoin/syscoin,syscoin/syscoin,syscoin/syscoin,syscoin/syscoin,syscoin/syscoin,syscoin/syscoin,syscoin/syscoin