Apple Silicon and universal builds

[Christian Calderon]

Add -universal to variants.conf

Sent from my iPhone

> On Jan 14, 2021, at 6:09 AM, Joshua Root <jmr at macports.org> wrote:
> 
> Mark Bestley wrote:
>> I have just got an Apple Silicon Mac Mini and am trying to install some ports
>> I am trying to use just arm code. However some ports put a +universal variant as the default. This would not be a problem except some ports do not build if universal e.g. python38 and icu.
>> Example ports that force unwanted +universal on are
>> llvm-9.0 - which I managed to build using the manual fix in the icu ticket
>> cargo which depends on python38. Now python38 works if arm build only.
>> How do I force things to build for arm only.
>> Why are +universal variants set as the default and how can you see which depenents are set this way (you can then force those to be single architecture)
> 
> This is happening when you install a port that does not support the arm64 architecture, which means the only way to proceed on arm64 hardware is to install an x86_64 version. This means that the dependencies need to support x86_64 as well, which results in them being installed with +universal.
> 
> If you don't want this to happen, you could set universal_archs to just 'arm64' in macports.conf. This will cause an error when you try to install any port that would normally trigger installation of a universal dependency.
> 
> - Josh