Changes to dependencies:  * Use a patched RISC-V-aware xmas-elf fork  * Use spin 0.6.0 as 0.7.0 appears to reach unreachable!() code    for reasons I need to investigate
Changes to dependencies:
 * Use a patched RISC-V-aware xmas-elf fork
 * Use spin 0.6.0 as 0.7.0 appears to reach unreachable!() code
   for reasons I need to investigate

diodesign/diosix