emulators/rvvm-devel: RISC-V Virtual Machine (development version)

RVVM is a virtual machine / emulator for RISC-V guests, which emphasizes
on performance, security, lean code and portability. It already runs a
lot of guest operating systems, including Linux, Haiku, FreeBSD,
OpenBSD, etc. It also aims to run RISC-V applications on a foreign-arch
host without full OS guest & isolation (Userland emulation).

This port holds a version of the project that is close to what is
currently in development.

Requested by: siva
See also: https://reviews.freebsd.org/D55356