Motivation / Problem

The provided emsdk patch for adding LZMA support to Emscripten is out of date and fails with the following error:

Step 3/3 : RUN cd /emsdk/upstream/emscripten && patch -p1 < /emsdk-liblzma.patch
 ---> Running in fc5f4dc7d2fc
patching file embuilder.py
Hunk #1 succeeded at 63 (offset 3 lines).
Hunk #2 FAILED at 198.
1 out of 2 hunks FAILED -- saving rejects to file embuilder.py.rej
patching file src/settings.js
Hunk #1 succeeded at 1212 (offset 15 lines).
patching file tools/ports/liblzma.py
The command '/bin/sh -c cd /emsdk/upstream/emscripten && patch -p1 < /emsdk-liblzma.patch' returned a non-zero code: 1

Description

This PR fixes that by pinning the Emscripten version to 2.0.10, similarly to what is being done for CI.

Limitations

It would be preferable to upstream LZMA support instead of relying on patching, which is IMO a fragile process. However, that is out of the scope of this PR.

Checklist for review

Some things are not automated, and forgotten often. This list is a reminder for the reviewers.

• The bug fix is important enough to be backported? (label: 'backport requested')
• This PR affects the save game format? (label 'savegame upgrade')
• This PR affects the GS/AI API? (label 'needs review: Script API')
  • ai_changelog.hpp, gs_changelog.hpp need updating.
  • The compatibility wrappers (compat_*.nut) need updating.
• This PR affects the NewGRF API? (label 'needs review: NewGRF')
  • newgrf_debug_data.h may need updating.
  • PR must be added to API tracker