http://mponpsecu5qaqu4s7chzbldsp6hu45pwecvr72m26xbf6lo3slqo6tad.onion/docs/INSTALL.html
If you do get failures, you should look at using the Changed Files package to replace the files which failed to patch. Please note that you will need to manually re-add any MODs to these particular files. Alternatively, if you know how, you can examine the .rej files to determine what failed where and make manual adjustments to the relevant source.