- Adding host primitives to a NeXtMidas option tree.
  1. Make sure that XBC is on the path.
  2. Create a `buildopt.mm` macro in the `mcr` area for the option tree.
     - Initially it can just look like this (be sure to change `MYOPT` to the name of the option tree):

           ! Calls the BUILDOPT;XBC to build the option tree.
           startmacro u:option["MYOPT"]
             BUILDOPT;SYS/mfn="nxm.xbc.mcr.buildopt.mm" ^option
           endmacro

  3. Create a `messages.cfg` file in the `cfg` area of the option tree. (Optional)
  4. Add the host primitive to the `host` area of the option tree. Then use `UPDATE` to add it to the dictionary (use `H` for the command support).
  5. Build the option tree:

         nM> MAKE ALL <OPT>

- Verifying a host primitive will run in XBC
  - The `CHECKXBC;XBC` command can be run manually to verify if a host primitive will run in XBC. See explain file for more details.