I already have all of the code for it, we have just been holding it off since it's a bigger change than we want for 3.6.9. It's actually part of a larger cross-platform upgrade to clean out a lot of the Windows only crap that exists in the code. SDL will be made to work on all platforms, but only as a build option in Windows, and nearly all of the MS-only things which need stubs/defines/typedefs for Linux/OSX will be abstracted to confined portions of platform specific code. It should make porting and debugging much easier, while also reducing and consolidating the code which is platform specific so that it's easier for general programmers to work with.
Those changes are likely to start happening soon after 3.6.9 goes official, so you'll see it in CVS builds before long. It just depends on how much time I have available, which hasn't been very much lately.