copy dlls on windows

lakefile.lean

@@ -18,6 +18,10 @@ target sdl.o pkg : FilePath := do
 target libleansdl pkg : FilePath := do
   let sdlO ← sdl.o.fetch
   let name := nameToStaticLib "leansdl"
+  if Platform.isWindows then
+    -- manually copy the DLLs we need to .lake/build/bin/ for the game to work
+    copyFile "vendor/SDL/build/SDL3.dll" ".lake/build/bin/SDL3.DLL"
+    copyFile "vendor/SDL_image/build/SDL3_image.dll" ".lake/build/bin/SDL3_image.DLL"
   buildStaticLib (pkg.staticLibDir / name) #[sdlO]
 
 lean_lib SDL where