retroforth/nga-c

I'm exploring some things around the VM implementation and tooling; this directory contains the relevant files for this. Things I'm working on in this: [x] Single file implementation [x] Modular I/O (enable/disable at compile time) [x] Faster opcode processing [x] Removal of image saving from the C sources [x] Building extended image w/o retro-extend in C [x] Assemble new image w/o retro-muri in C [ ] Support for embedding device words in the C source [ ] Embed image in the C source using tool written in Retro

Specifics:

Retro's build process is a little messy. We first compile the assembler, then retro-extend (which is an Nga-in-C, with a reduced set of I/O). These are used to assemble the kernel, merge in the stdlib and any device words, then the VM is compiled, user-level additions are added to a new image, and then the source is updated before being rebuilt.

In this, the VM is built, then is used to assemble and build a new image, eliminating the need for separate retro-extend and retro-muri binaries.

In the longer term, there is benefit to having a standalone set of supporting tools, so I'm not going to eliminate them, but using Retro itself for more is something worth doing IMO.