Okay, here it is on GitHub public repository. I registered on GitHub just for that; however, don’t get your hopes too high, it’s still in early alpha state - it’s not “full-featured gwbasic / qbasic compiler” yet, the README files and documentation are way, way too promising: https://github.com/ronen-blumberg/rbbasic

The code is on my HDD, and a portable version with Mingw32 and SDL2 (almost one GB in size) on my USB stick

Yep, that’s what you have in FreeBASIC subs (void functions) and functions (that return a value). FreeBASIC is actually C programming in disguise; it’s C with basic syntax and very powerful, plus any C library can be used with it (you just need to have the correct .bi header file for it)