Apple Silicon and universal builds

[Mark Bestley]

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)

>From ppc days I thought that universal wen in a conf file and did not produce variants.

Thanks
Mark