Ned Deily writes:
I don't think OS X support should be a gating factor in deciding to move ahead with C99 adoption but it does point out that there might be more ramifications to this decision.
I may be talking through my hat here, but Apple has been using LLVM for several major releases now. They seem to be keeping the GCC frontend stuck at 4.2.1, though. So just because we've been using GCC 4.2.1 on Mac, including on buildbots, doesn't mean that there is no C99 compiler available on Macs -- it's quite possible that the available clang frontend does already support the C99 features we would use. I suppose that might mean fiddling with the installer build process as well as the buildbots. Also, it seems like it's been a decade since a C compiler came standard with Mac OS X -- you need to download and install Xcode or at least xcodebuildtools separately. So unless the Macs are quite ancient (fvo ancient = 5 years old), at least at one time they were upgradeable by installing Xcode. Of course Mac users may not be willing or able to upgrade Xcode, but at least the possibility is worth investigating.
What may be more difficult is to judge the impact on other platforms that don't get as much attention from most of us. For this to move forward, we need to be able to state what the impact to current users will be.
We could post a poll to python-list (to be hosted on surveymonkey or similar, *not* back to this list!), explaining the proposal and asking "what is your platform?", "what compiler and version do you use?", "does it support C99 (perhaps with switches)?", "if not, can you upgrade to one with C99 support?", and "if you can upgrade, how much pain would it be to upgrade?" I guess the last one would take values from "I'd be annoyed for less than 10 minutes then forget it" to "enough so that I wouldn't upgrade Python". I suppose one intermediate answer might be "I'd have to maintain a separate compiler just for Python."