Very basic for now, completely untested on everything not named Gentoo
Linux. In theory we shouldn't need QT_STATICPLUGIN anymore since I
compiled it in a way that doesn't suck (unlike MSYS2...), but we'll see.
I'll cross that bridge once I have access to my desktop again.
macOS is entirely untested but should also work. Multimedia is
implemented too, works on both Windows and macOS, though we don't
actually use it so it doesn't really matter.
Also todo: use this in CI, specifically for macOS and Windows/MinGW.
Linux doesn't need it since we have qtbase-mini which is smaller than
this (since I added more features into this one).
Furthermore, some options have changed, notably w.r.t LTO and faster
linker, which are now handled directly in the modules.
Signed-off-by: crueter <crueter@eden-emu.dev>