Patching & compiling an open source

I have the source code for an open source tool that I need help compiling. It's crucial that the compiled tool is compatible with macOS. Additionally, I have a patch that needs to be applied. I would require concise documentation that outlines the key steps to apply the patch and compile the tool.
Expertise in C, open source tools, compiling, and patch application is essential. The ability to provide clear and concise documentation is also a must.