.NET 8: Enable experimental MacOS source build

[mmitche]

Describe the Problem

Unified build seeks to expand the number of platforms that .NET 8 can source-build on, and replace the existing Microsoft official build with source-build. Part of this is enabling a build for MacOS.

Describe the Solution

MacOS source build (with a number of prebuilts) might actually be functional today. It is in use in some capacity for homebrew.

[dotnet-issue-labeler]

I couldn't figure out the best area label to add to this issue. If you have write-permissions please help me learn by adding exactly one area label.

[MichaelSimons]

[Triage] @mmitche, @directhex - Some work was done in this space earlier. Has this been completed? If not what remains?

[MichaelSimons]

gentle ping @mmitche, @directhex - what work remains here?

[mmitche]

I'm not sure. @directhex What work got done here? Is there a branch anywhere?

[directhex]

#3217 is the state of the art in my work. I've had other commitments for net8

[MichaelSimons]

What should we do with this issue? Close (indicating we did what we expected or plans have changed) or move to .NET 9.0?

[directhex]

Either is fine.

[omajid]

@asbjornu hey, have you looked at building .NET 8 (using https://github.com/dotnet/dotnet/) on macOS ?

[MichaelSimons]

Closing as no further experimental work is intended in the .NET 8.0 timeframe.

[asbjornu]

@asbjornu hey, have you looked at building .NET 8 (using https://github.com/dotnet/dotnet/) on macOS ?

@omajid, I just tried it out now, and everything worked until ./build.sh --clean-while-building --online, which fails with the following error.

[omajid]

Thanks, @asbjornu . That error looks like a missing dependency?

In case you aren't aware, though, we don't have any plans for implementing macOS support for building .NET from source. Are you planning to add .NET 8 to homebrew as well? If so, you will have to find and fix any issues that come up. We will probably accept any macOS patches, but just don't have the manpower or the time to fully implement/test macOS support ourselves.

[asbjornu]

Right. From dotnet/runtime/…/macos-requirements.md I can see that I have to clone the dotnet/runtime erpository and run brew bundle --no-lock --file eng/Brewfile to have all dependencies installed. With that done, I get the following build error.