Another noob here, so maybe a stupid comment, but...
I compiled OpenXcom under Linux two days ago for the first time using guide on
https://ufopaedia.org.
It was super easy.
And yesterday I even compiled a windows EXE under Linux, using Mingw-w64 (on 32-bit Kubuntu btw.).
That was a bit more complicated for a noob, but no rocket science.
In both cases it was either a pre-compiled sdl, or the cmake+make did everything for me... I don't even know.
So, the questions:
- why do you want to compile it yourself?
- isn't the official guide enough?
- do you want it only because of 64bits? if so, just saying you won't get any benefits from it compared to 32bits