External module api

[bernd-herzog]

This pull requests adds the external module api

[bernd-herzog]

This pull requests is still work in progress

[gullradriel]

I love what's coming , many thanks to you !

[bernd-herzog]

the sources for the standalone app and the esp32 firmware can for now be found at: https://github.com/bernd-herzog/mayhem-external-module/tree/external-module-api

[bernd-herzog]

I created a new repository in the mayhem organization with a nice name: PortaPack - Module Develoment Kit
https://github.com/portapack-mayhem/mayhem-mdk

[gullradriel]

Good idea !
Maybe @htotoo can do the same for his USB serial stuff ?

[jLynx]

Nice work here!

[gullradriel]

Just for the record and the history, why I do not like "pragma once"

Platforms/Compilers Known Not to Support #pragma once:

• Turbo C++ (classic versions)
• Watcom C++ (older versions)
• Borland C++ (classic versions, although newer Embarcadero C++ Builder supports it)

Some older or niche embedded systems compilers may not support #pragma once, or it may be inconsistent:

• Microchip MPLAB XC in older versions.
• Keil C51, an older compiler for 8051 microcontrollers, doesn’t support it.

Older versions of GCC and Clang:

• Extremely outdated versions of GCC (pre-3.4, released before 2004) and Clang may lack full or reliable support.

And this has bitten me a few times:

• Compilers using #pragma once rely on the assumption that files have unique paths. Network file systems, file systems with symbolic links, or certain virtualized environments (like those in cloud builds or CI/CD environments) can cause problems, as #pragma once can get confused by symlinks or different paths to the same file.

Last, some compilers not adhering to modern C++ standards (before C++98) may lack support.

That aside, pretty good job :-)