Needed for Çoqoban #sorry :)

It's a bit slow but I was bit by that when obsolete files were there mixed with
those from a newer version.

Use jsoo debug flags like in the worker build.

Note: esbuild arch-dependent deps exist; need a relatively new version of
NPM (e.g. 9.6.x).

Work around it by setting the problematic import as external.

[build] Bump SerAPI and Coq to 8.17.1

Add Gist sharing support

[ci] Use aptitude's solver for 32 bit gcc toolchain install

`apt-get` solver cannot realize the constraints (and package
removals), which prevents install of the 32-bit gcc toolchain.

`aptitude`'s solver works for now, so we use it.

This kind of package conflicts do remain a big PITA.

`jscoq.js` is needed.

Signed-off-by: Elad Kinsbruner <kinsbruner@campus.technion.ac.il>

Added standard c_flags to jscoq_extern.

In scratchpad only.
Closes #326.

New in 8.17.

Instead of `.cjs`; enough with this nonsense.