Creating a library

I’ve been trying to create my own standard code library using ESP 7.4.5.

However when I create a project for a Static Library (whether I select gnu, or gnu for Windows) I end up with a project generating code for the PC, rather than for ARM.

It seems that I need something similar to a Net+O/S Platform Project, but generating a standalone library file that I can link in.

Am I missing something, or is this not possible? Or is there another way I should be doing it?