Has anyone tried to install the SDK under WSL2? I can get through all the steps but when I build a freshly made Alloy app I immediately get this:
Running Moddable prebuild.
Running mcrun -m ./src/embeddedjs/manifest.json -f x -p pebble/emery -t build -o ./build/mods/emery/mcrun -s tech.moddable.pebble
-p pebble/emery
Error in Moddable prebuild: [Errno 2] No such file or directory: ‘./build/mods/emery/mcrun/bin/pebble/release/embeddedjs/mc.xsa’
There was one person that had the same issue, their solution was to set it up in a regular Linux installation then copy over all the files 
what happens if you uninstall the SDK and install it again?
I ran into the same problem and it turned out to be missing dependencies for me.
If the make command is missing on the system, the build will fail with exactly this error. After installing the basic development tools / C(++) SDK on my distro, I am now able to build my watchface.
On openSUSE that was
sudo zypper install -t pattern devel_basis
If you’re on Debian or Ubuntu, the equivalent would be
sudo apt install build-essential
Don’t believe you have the same issue I had - but maybe this still helps you or someone else.
I couldn’t build apps via WSL the other day, turns out my WSL itself needed to be updated.
I believe I just ran wsl --update in CMD and when I launched WSL again everything pretty much worked.