As I'm now on my laptop with access to the two simple programs; for text output:

  import encodings
  var hello1 = convert("Hellø, wørld!", "850", "UTF-8")

  # Doesn't work - seems to think current codepage is utf8.
  var hello2 = convert("Hellø, wørld!", getCurrentEncoding(), "UTF-8")

  # Outputs correct text:
  echo hello1
  # Outputs corrupted text:
  echo hello2

(And simply outputting an unconverted string fails, like hello2 does).

As for the linking problem I had, the main issue is that it seems to be harder than it probably should, to get started with the GUI-programming with nim on windows. The following code works, provided one manually obtains sdl2.dll (and sdl2.lib for static linking) - however, even with static linking flags (no errors), the resulting exe still depends on the presence of sdl2.dll:

  import nimx.window
  import nimx.text_field
  import nimx.system_logger

  proc startApp() =
    var window = newWindow(newRect(40, 40, 800, 600))
    let label = newLabel(newRect(20, 20, 150, 20))
    label.text = "Hellø, wørld!"
    window.addSubview(label)

  runApplication:
    startApp()

With sdl2.dll (and .lib) in the same folder both of these work:

nim --threads:on --dynlibOverride:SDL2 --passL:SDL2.lib c -r win.nim

nim --threads:on c -r win.nim

but both fail without sdl2.dll present (ie: the "statically" linked exe still depends on dynamically loading sdl2.dll).

And there's so far no easy way of getting a "supported" sdl2.dll to go with the nim compiler - as far as I can tell, neither "nimble install sdl2" or "nimble install nimx" provide a way to get the sdl2.dll and/or C source code to compile it.

But perhaps managing DLLs and such is considered to be out-of-scope for nimble/nim package manager for now.

Ha, your comment was my first introduction to Nim but it looks interesting so I "brew install nim" and tried your test (thanks!) with "nim c test.nim && ./test" on macOS and my results is the opposite of your: hello1 is garbled while hello2 works.

I bit of googling found the next steps "nimble install minx" but for compiling your win.nim example I had to use "nim --noMain --threads:on c -r win.nim" but the result worked. However AFAIK, there's no official way to make statically linked binaries on the latest macOS.