I think you should consider removing the entire memfill functionality if you remove the backstory/docs for it.

That custom memory fill thing has lost its purpose. valgrind and ASAN are superior tools to catch memory issues.

I will try to work on this until Saturday. I am currently a bit busy

Found some time actually! This is ready for merge I think

You need to remove the use of those macros too:

memdebug.c:131:5: error: implicit declaration of function 'mt_malloc_fill' is invalid in C99 [-Werror,-Wimplicit-function-declaration]
    mt_malloc_fill(mem->mem, wantedsize);
    ^
memdebug.c:279:5: error: implicit declaration of function 'mt_free_fill' is invalid in C99 [-Werror,-Wimplicit-function-declaration]
    mt_free_fill(mem->mem, mem->size);
    ^
2 errors generated.

You need to remove the use of those macros too:

memdebug.c:131:5: error: implicit declaration of function 'mt_malloc_fill' is invalid in C99 [-Werror,-Wimplicit-function-declaration]

    mt_malloc_fill(mem->mem, wantedsize);

    ^

memdebug.c:279:5: error: implicit declaration of function 'mt_free_fill' is invalid in C99 [-Werror,-Wimplicit-function-declaration]

    mt_free_fill(mem->mem, mem->size);

    ^

2 errors generated.

Sure... but my cc haven't reported a single error on that patch 😟

Then you must've forgot to build it debug-enabled - as you can see in the CI...

Thanks! (I edited the commit message somewhat)