How to add to C++ project additional compiler flags?

Yeah I have tried that, put it in both the *.Target.cs and the *.Editor.Target.cs but it doesn’t add the argument. Although it does seem to remove some?

This is WITHOUT AdditionalCompilerArguments = “/ Zc:preprocessor”;
(There is the /Yu “file path” at the end)

And this is WITH AdditionalCompilerArguments = “/ Zc:preprocessor”;
(No /Yu, so adding this line ^^^ removes /Yu?)

Really strange.