Okay, I've managed to get the compiler to build the project, although I don't think it's done it correctly:
--macro include('lime')
-cp openfl
-cs openflbuild
-D dll
(Yes, I am attempting to build the OpenFL project to the C#, mainly to make a visual editor for video game development)
The output dll is 47KB, and the source files include just the Haxe source, none of the OpenFL source files are found no where, which is unusual since I did use the "-cp openfl" to target that folder as the folder to build with all the haxe source code files.
Although maybe there is another way to parse files in the Haxe compiler...