Way back then I created a couple of patches to apply certain changes to some files – but now I needed to created new patches … and how did I create those patches once again? Especially how to create a patch, which can modify several files at the same time?!

OK – after some google-ing I figured it out:

diff -c2 old_file1 new_file1 > patch
diff -c2 old_file2 new_file2 >> patch

This allows me to update both files with just one patch:

patch -p0 -b < patch

Good to know!