Add build for arm64?

[andrewpauling]

I noticed there is no build for arm64 on conda-forge for Macs with Apple Silicon. I managed to build libmo_unpack and mo_pack from source successfully on an M1 Macbook Pro, but it would be nice if a build could be added to conda-forge.

[trexfeathers]

Hi @andrewpauling, thanks for getting in touch.

I'm afraid the SciTools development team is stretched very thin at the moment, so we're unlikely to have resource for this in the short-/medium-term.

We will certainly keep this issue open - it's a useful record of a user requirement!

[andrewpauling]

Hi @trexfeathers, thanks for the quick reply.

No problem, totally understand. In case it is helpful for someone who does eventually look at this or others who run into this problem, I was able to build and install libmo_unpack and mo_pack from source successfully on my M1 Mac by following the build recipe for OSX at https://github.com/conda-forge/libmo_unpack-feedstock and the instructions for installation from source for mo_pack. I made a repo containing a script to build libmo_unpack and instructions for installing mo_pack into a conda environment at https://github.com/andrewpauling/install_mo_pack_applesilicon. Hope someone finds it useful.

[bjlittle]

For this we'd have to support building wheels, and cibuildwheel would be a friend here ... however, the immediate complication would be packaging the libmo_unpack pure C dependency first.

Not impossible, but needs some thought 🤔

[ocefpaf]

Not impossible, but needs some thought 🤔

Maybe you can:

1. build libmo_unpack for arm64, osx-arm64, etc using the conda-forge structure;
2. build the wheel using the conda-forge package like in this.

That would get both wheel and conda package in sync and make it easier to maintain the extra c-libs builds in a single place.