Deprecated does not mean unsupported. Apple does still support both PPC and 10.4, and so does our SDL dependency. In fact, the 10.4 SDK is still delivered as part of XCode, it's just optional instead of automatically installed.
Perhaps I'm missing something there? I couldn't find 10.4 SDK anywhere on my Mac partition, and my Xcode refuses to comply as well.
You are, of course, free to build things however you see fit. However, i'd like to recommend that the project continue to support two steps back from the current version of OSX. I don't think that this would prove to be a huge burden.
It is a burden in terms of having to deal with SDL dependencies, some of which I had to recompile manually in order to make sure everything worked as intended. And even if manageable, I still see no viable reason why bother in the first place, no offence. If you take a look at these statistics -
https://update.omnigroup.com/ (Overall > Major Version), you will notice that 10.4 constitutes only 21.8% of OSX market share and is dropping steadily. Of course, these are not backed by Apple, but I'm sure they are quite representative nevertheless. The aforementioned being taken into account - personally, I think it is not worth the hassle, at least on my part. On the other hand, if you feel comfortable about making such kind of a contribution - you are definitely welcome.