Once you release something what gets at least a little bit popular, you can expect to receive fixes in various strange forms. Since I started to use Git for Gammu development merging all these crazy things is much more easier.
The problem with these changes in past was that they are generally based on some random old versions (for example random daily snapshot). Now I just find the right place in history where to start (ChangeLog usually gives good hint where to search in the history), create branch and start to apply changes I received.
I worst case (like it happened today) the "changes" is whole tarball with
different changes made to different files. Fortunately I recently found great
git add -i, which allows me to pick whatever changes I want from the patch.
When all this is done, all I need is to merge changes back to master and Git
is usually clever enough to handle it.
PS: And yes, I'd really love if people would be able to send me series of patches, but it does not seem to happen in near future.