Unable to move mesh elements into separate files for reusability (IDFGH-10805)

[parksj10]

Answers checklist.

• [X] I have read the documentation ESP-IDF Programming Guide and the issue is not addressed there.
• [X] I have updated my IDF branch (master or release) to the latest version and checked that the issue is present there.
• [X] I have searched the issue tracker for a similar issue and not found a similar issue.

General issue report

I have the following code:

// note: this implicity defines onoff_pub_0 as a static
ESP_BLE_MESH_MODEL_PUB_DEFINE(onoff_pub_0, 2 + 3, ROLE_NODE);
static esp_ble_mesh_gen_onoff_srv_t onoff_server_0 = {
    .rsp_ctrl.get_auto_rsp = ESP_BLE_MESH_SERVER_AUTO_RSP,
    .rsp_ctrl.set_auto_rsp = ESP_BLE_MESH_SERVER_AUTO_RSP,
};

// ...

static esp_ble_mesh_model_t root_models[] = {
    ESP_BLE_MESH_MODEL_GEN_ONOFF_SRV(&onoff_pub_0, &onoff_server_0),\
    // ...
};

I'd like to be able to isolate these definition into separate file, and root_models in a separate file (to allow for reusability of code), but I can't seem to get around accessing static variables from another file (and yes, I've read a lot of posts on StackOverflow about using statics in C for encapsulation)... Is there any better option when the library I'm using implements static variables in their macros?

FYI, here's a more complete example if someone wants to propose a more general architecture approach...

[ankit-thealchemist]

I am not able to understand what we want to achive here.