生成make文件

I have a golang CLI program which generates a makefile to a specific project. While this works, there is an issue when the project already has a makefile. Of course I can check that in advance to avoid collusion, but how is it suggested to do it?

I'm not an expert in makefiles, but how can I create second makefile (maybe with the project name or something) that user can run via make (I guess with additional steps or info to the terminal)