[REQ] Generation of plain, dependency-free C code for microcontrollers

I'm using the openapi-generator extensively, but have so far been held back by the inability to generate dependency-free C-code that an be loaded onto an ESP-32 or similar, large microcontroller. Every server generator pulls in so many dependencies that the microcontroller's memory would filled up by the dependencies' code alone, if it were even possible to compile these dependencies for the target CPU at all. In order to open up the IoT to openapi, a simple C server stub would be a good solution.

It would, to be universal, probably need to work like this:

int default_api_process(const char *method, const char *url, const char *inputBuffer, int inputSize, char *outputBuffer, int *outputSize);

where the return value would be the HTTP status to send, the outputBuffer would be filled with the fully formatted (with all headers) html document, the inputBuffer represents the request body and the URL is the complete URL to process.

That would be useful on ESP8266, ESP-32 and other wifi-enabled IoT CPUs.

Using C++ would be possible as well, however, these small CPUs have no heap and therefore no operator new.

The issue names no files, tests, or generator entry points. Review the existing server-generator architecture and the proposed default_api_process signature first; done means a dependency-free C server stub can be generated for microcontrollers such as ESP8266 and ESP-32 without heap allocation.