[R-SIG-Mac] Announcement: R-devel "sonoma-arm64" Mac builds

[Mikael Jagan]

> Date: Sun, 14 Dec 2025 11:39:16 +1300
> From: Simon Urbanek<simon.urbanek using R-project.org>
> 
> 
> 
>> On 14/12/2025, at 11:24 AM, Jeroen Ooms<jeroenooms using gmail.com> wrote:
>>
>> On Fri, Dec 12, 2025 at 3:20 AM Simon Urbanek
>> <simon.urbanek using r-project.org> wrote:
>>
>>> The goal is to remove the existing big-sur-arm64 R-devel binaries in favor of the sonoma-arm64 R-devel build. Since we are still far away from the R-devel release, all this is considered experimental and may change in the future (possibly Fortran upgrade is in the cards), but given that this is not a minor change, I want to give others the opportunity to test the new setup and comment as appropriate.
>> Thanks. Some quick observations:
>>
>> The x86_64 build of r-devel onhttps://mac.r-project.org/ is almost 2 months old?
>>
> Should be fixed now.
> 
> 
>> On arm64, using the latest R-devel-arm64.pkg on a machine with macOS 15 and Xcode_16.2, I get the following error for all packages with compiled C code:
>>
>>   error: invalid value 'gnu23' in '-std=gnu23'
>>   note: use 'c2x' for 'Working Draft for ISO C2x' standard
>>   note: use 'gnu2x' for 'Working Draft for ISO C2x with GNU extensions' standard
>>
> 
> That is expected, you'll need at least Xcode 16.3 since 16.2 is LLVM 17 while 16.3 is LLVM 19 which, as has been discussed at length, was a big breaking jump. As noted, what is actually used is Xcode 26.x so that would be recommended (albeit not required).
> 
> It does raise an interesting point, though: macOS 15 is not an issue since you can install all the way to Xcode 26.3 without problems, but macOS 14 (which is our designed target) only runs Xcode 16.2. However, the whole point of moving the target forward was that we upgrade from Xcode 16.2 since that's what we used for the Big Sur build, so sticking with it would defeat the whole purpose. So, would anyone be unhappy if we simply declared macOS 14 as the run-time target, but development needs macOS 15 for the compiler support? It's not ideal, but the only other way would be to deliberately disable C23 support - it's doable, though.
> 

I am still running macOS 14 with Xcode 16.2, so I will be unhappy for the time
it takes to upgrade - not only macOS but also whatever I have installed under
/usr/local.  I delayed so long because Xcode 16.3 broke so much ...

But I really ought to start testing with the newer toolchains, so I will just
upgrade and be done with it.

Mikael


> Cheers,
> Simon