Creating a patch file from a diff of 2 folders

If you have two directories a and b that are similar, and you want b to be the same as a, you can create and apply a patch with:

$ diff -ur b a > ba.diff
$ patch -i ba.diff

Suppose you have directories local (containing your local version of upstream1.0), upstream1.0, and upstream1.1. To create and apply your changes to upstream1.1:

$ diff -ur upstream1.0 local > my.diff
$ cd upstream1.1
$ patch -i ../my.diff 

Check the documentation for patch, and try to convince the upstream maintainers to use git. Things will be much simpler if you can use git tools to work with your local repository.