Visual Studio Code C++ Syntax Highlighting Header Include Path

Question

I'm writing a project in C++ using VSCode and want to include certain headers in my files. Normally I'd be able to do this, but the headers I need are in a separate folder path than the one I'm working on, like this:

PROJECT FOLDER

• src
  • vendor
    • "resource.h"
  • tests
    • "main.cpp"

I want to have the syntax highlighter search the whole of 'src' for includes. I am not using VSCode for compilation, I have clang and a raw makefile to do it through the terminal.

P.S. theres no topic for VSCode or VSCommunity so I put it under windows 10