doesn't work if opam sandboxing is enabled

[avsm]

Just a quick PSA to anyone trying this that it'll fail if opam sandboxing is enabled (the default on macOS/Linux) in the OCaml cross compiler build phase (as it tries to write into a read-only area directly in the switch). I'm just investigating how to fix this, but thought I'd record this quickly for anyone else encountering a build failure.

It's kind of magically good once I turned sandboxing off :-)

[chris-armstrong]

I've seen this issue as well: turning off the sandboxing does seem to help. In the Github actions, I avoid breaking the sandbox by setting the Zig cache paths to be in /tmp ( it defaults to the user's home directory).