Ok, so I know the code, and how it was written, and let's put multiplayer aside for a moment. The game was written for Intel x86, without any thought towards future expansion and portability. If it does work on ARM, it's because I have been practicing portable coding from the beginning when ever something was done. So that's good, at least we are heading in the right direction. But as the README states, we don't support ARM (and since there are several, which ones??). I have never tested it, and...
Cross-platform multiplayer (i.e without 387 FPU requirement)
I understand your issue, and really, you can't just do that. I can't support ARM right now, so unfortunately I can't address the request here.
curl.h needed
Configure is checking for curl correctly. The problem is WebService needs to be skipped during make because it's curl only. The fix is to just reorder when the automake conditionals get set so it does actually get disabled. This has been done.
ConfigAdv: Add option to enable the scenario editor.
configure: Process automake conditions after build options are set.
NationArray: Update Nation's king_leadership when collecting stats.