This has been tested in the RC2014 emulator. I could edit blocks with
the Block Editor and they would correctly be written to SDC.

Goes through initialization in RC2014 emulator.

All of that should help me implement sdc support much faster in
Forth.

I now get to "fls" in recipes/rc2014/sdcard!

so far, it goes through initialization with the rc2014/sdcard recipe.

Why didn't I think of adding it before?

This makes the emulator suitable to run the base SMS recipe.

Previously, it would never get out of the event loop.

It seems to be picky about where it accepts its link flags.

VDP kinda works. Can see the Collapse OS prompt with SMS base recipe
if `STDIO_GETC` gets replaced with infinite loop (no input emul yet).

I implement the screen using XCB which is much more friendly
than z80e's SDL+CMake for development machines that want to install
minimal dependencies (for example, a port-less OpenBSD rig).