MD Debugger: Enable experimental Sega 32X support

[vladikcomper]

A little known fact: there exists a sega-32x branch of MD-Modules.

Unfortunately, it was maintained as a separate version and is now largely outdated. Luckily, the changeset is relatively small and 32X support can thus be implemented via a compile flag.

ConvSym is flexible enough to support a symbol generation for 32X projects, only Error Handler blob has to be modified to handle stack differently. Some incorporated patches will also benefit mainline Error Handler blob as well, as it enables support for stack pointers below $FFFF8000.