Since GTK2 is getting older and has been superseded by GTK3, this pull requests adds support for it, still supporting GTK2 as a fallback. Even though there aren't many actual breakages when building with GTK3 (since it mostly just deprecates functions), I've replaced all deprecations with their replacements suggested by the GTK devs.
As a side note, I noticed that with GTK3, the window didn't want to center. I'm not sure where this issue originates from, as it works fine in GTK2, but I fixed it by manually moving the window to the center of the screen. Using GTK_WIN_POS_CENTER_ALWAYS instead of GTK_WIN_POS_CENTER also works.
Feedback is welcomed, and might I say good job to you, sirs, for maintaining Zandronum!
Thanks! Except for some trailing tabs/spaces, the patch looks. I don't have a system at hand where I can test whether the GTK3 support works though. I'll ask Dusk or Blzut3 whether they can compile and check this briefly.
How do I download this as a raw diff?
EDIT: Nevermind, pulled the changesets to my working copy.
Also, you should consider submitting this to ZDoom as well.
For some reason I had gtk_check_version for runtime usage stuck in my mind and forgot completely about the feature macro's. I've updated my pull request to use those instead. As for the spaces, I have a pretty aggressive editor that seems to want to make the entire file consistent on save, looking at the diff I seem to have been successful in killing that habit ;-).
Not sure if ZDooM would be interested (as they don't seem to "officially" support Linux apart from the fact that it just happens to work there), which of course doesn't mean I won't consider submitting a pull request there anyway :). Also a neat side effect of using GTK3 on GNOME seems to be that the dark theme is used if you have it enabled.
I don't know where you get the impression we don't support Linux. One of the devs (me) uses Linux as his primary development machine.
Well, even though it is advertised on the homepage of ZDooM in small letters under "If you have Linux, it works with that too.", the downloads section doesn't mention Linux support anywhere and there seem to be no official binaries (like Zandronum has). Granted, the tar.gz does mention "GCC", however what a lot of people do (including me, as you've probably guessed) is immediately venture to the downloads page to check if there is Linux support if it isn't immediately clearly visible on the first page (which is also is "News" and not "About"). There you see a big Windows flag and an Apple logo, but no Linux penguin, which had me fooled for a long time until I discovered it actually runs just fine on Linux. I took "GCC" in this case as just "GCC under Windows".
Also, using Linux as your primary development machine doesn't mean it runs on Linux; you could very well be cross-compiling or getting it to work in the first place ;-).
OK, I'll give you that the home page is kind of confusing. There are 90% official binaries in the same Ubuntu apt repository as Zandronum. I tried to convince Randy to link to it twice and he said something along the lines of not knowing how to make it work on the page.
I assure you I have no cross compilers installed. Been using Ubuntu since 2007/2008 and haven't looked back.