Each time I revved a new version, I had to copy the patch files from the earlier versions and then manually update them so they were correctly applied to the later code base. Overall this was not a huge job as the code doesn't change much.
The jcmbkbc fork hasn't been touched in forever so I would use both that and the espressif fork as references, but I would check out the core crosstool repo itself and start from there. As usual, the Espressif guys simply hack the core code rather than making something that is future proof - at least the jcmbkbc fork isolates the patches so they can be used with later gcc versions, albeit manually.
If you would like a web call together to go through it I would be happy to do that if we can work out a common time