Orix SDK
It provides macro to help assembly coding for Orix :
https://github.com/assinie/orix-sdk/
The main way to handle orix-sdk is to add it as gitmodules (for example in a "dependencies folder")
Install in a project
mkdir myasmproject
cd myasm_project
mkdir dependencies && cd dependencies
git clone https://github.com/assinie/orix-sdk.git
Load Orix SDK
you just need to load macro file in your code (and telestrat.inc from cc65):
.include "telestrat.inc"
.include "dependencies/orix-sdk/macros/SDK.mac"