QSOE/N v0.18: a second board, and a second compiler

Two things happen in this release, and they turn out to be the same thing seen from opposite ends. QSOE/N boots to an interactive shell on the SpacemiT K3 — the second piece of silicon it has ever run on, after the SiFive Unmatched. And the entire operating system — kernel, taskman, libc.so , the runtime linker, every program under /bin and /sbin — now builds with a second compiler, jmcc, and…