Allow files bigger than 2GiB for --patch-from option

[JuniorJPDJ]

This is very crucial for my usecase to have patches for files bigger than 2GiB. I'm trying to find suitable open-source and supported smv alternative as I've a big collection of files very similar to each other (100M patches on >5GiB files). Is it hard to allow dictionaries larger than 2GiB? (As I suspect this is the limitation reason). AFAIK 2 gigs is signed int size limit.