All of these are options that are specific to our ghactions builds and not something we want downstream and package maintainers to be locked into using.
Both the debug and release jobs would upload artifacts, with the same name, which ghactions of course accepted without question. Snapshot 240 happens to have been released correctly (so all binaries are release builds), but that's just luck. I'd thought I'd fixed this problem with another commit, but turns out I hadn't.
Also factor out a bunch of variables so I won't mess up in the future.
Command line is limited in length on windows so meson/ninja puts it in a response file and passes that to the linker instead. Only problem is, ninja -v displays only the part of the command line where it tells link.exe where the response file is, not what's in the response file. So I just had the script print it. Care must also be taken for the script to properly fail if ninja fails, but not before the command line is printed.
Also add /GL and /LCTG to msvc command lines because they can't hurt. Right?
Also restructure meson.build and the ghactions workflow a bit, and enable -ffunction-sections and -fdata-sections.
Note that starcatcher uploads have not been tested and most likely don't work.
Also fix the first mouse click not being detected on windows with sdl 2.0.20. Apparenlty, we need SDL_HINT_MOUSE_FOCUS_CLICKTHROUGH set to 1 for it to be detected.
