It might be related ... looks like the SDL folks introduced that "SDL::SDL"
stuff to the autoconf part just some few months ago:
https://github.com/libsdl-org/SDL/commit/6d1dfc8322f752
And SDL 2.24 was the first release where this was shipped. Maybe you could
try downgrade to 2.0.23 or try a version compiled with CMake instead?
I tried with SDL from git, still same issue. I'll try compiling SDL with CMake.
With SDL compiled with CMake the problem goes away. I have to fix my build scripts then.
Both 32bit and 64bit are working now.