How do I add csc.rsp to my project?

I’d like access to System.Data.DataTableExtensions. My understanding is to do this, I need to add that to the csc.rsp file of my project.

When I try to import csc.rsp as an asset, it doesn’t let me (it literally doesn’t show up in the file browser) and there doesn’t seem to be a way to create an arbitrary file in the project.

How do I actually add a csc.rsp file to my project?

If you need this to use external dll than you can do this without csc.rsp file but with adding “Additional Compiler Arguments”.

You can check this link:

Or my answer in unity forum: