Ok so the way I do it is this:
in phabricator(https://code.wildfiregames.com/D5282), click "Download Raw Diff", this will open a plain text file in your browser.
Copy the contents of the file
navigate to your SVN directory
Paste the contents into a new file with the extension '.diff'
type 'svn patch ABC.diff'
now at this point, some files should print to console with 'U' for updated. bigger patches might have conflicts, but that shouldn't be the case here. Since this patch modifies the engine, you will need to also build the game: https://trac.wildfiregames.com/wiki/BuildInstructions