Some keyboards misuse _user functions by defining them in the base files
instead of the corresponding _kb functions (especially led_set_user and
matrix_init_user). Until this is fixed (#5148), I've removed definitions
in my userspace that could cause linking collisions.
This is a place for users to put code that they might use between keyboards. If you build the keymap mine, /users/mine/rules.mk will be included in your build, and /users/mine/ will be in your path - keep these things in mind when naming your files and referencing them from other places.