debian: Install emscripten

Closed Ben Gamari requested to merge wip/emscripten into master

Here we add support for installing emscripten to the Debian images. Note that the user must source $EMSDK_ENV_SH to use the emscripten toolchain.

Addresses ghc#22128 (closed).

Note that we don't yet upgrade LLVM 15 as binaries are not yet available. Supposedly binaries will be uploaded soon.

Edited by Ben Gamari

Merge request reports