[dev] Add patches for WASM support

[IsabelParedes]

Checklist

• Used a personal fork of the feedstock to propose changes
• Bumped the build number (if the version is unchanged)
• Reset the build number to 0 (if the version changed)
• Re-rendered with the latest conda-smithy (Use the phrase @conda-forge-admin, please rerender in a comment in this PR for automated rerendering)
• Ensured the license file is being packaged.

[conda-forge-webservices]

Hi! This is the friendly automated conda-forge-linting service.

I just wanted to let you know that I linted all conda-recipes in your PR (recipe) and found it was in an excellent condition.

[h-vetinari]

To understand, you want to build a compiler that runs on linux and compiles for emscripten? Not sure if our clang already supports that target; in any case, building clang/flang/mlir in the same feedstock will almost certainly time out.

We'll need to come up with a larger-scale plan for how we want to support wasm/emscripten in conda-forge, but as an experiment, I could imagine pushing this into a separate label conda-forge/label/llvm_<...>

[IsabelParedes]

you want to build a compiler that runs on linux and compiles for emscripten?

Exactly.

I don't think it's necessary to rebuild clang. Emscripten uses clang internally.

For pushing to a new label, could I make the changes in this PR or should that be separate?

[IsabelParedes]

@conda-forge-admin, please rerender

[IsabelParedes]

Hi! I'm not sure why this is failing when it passed before and there are no changes...
Anyhow, closing this for now to create a new flang variant in a separate PR.

[h-vetinari]

The linux failures I'm not sure about, but the windows builds time out on this feedstock quite regularly unfortunately.