support unix endpoint path with more than 104 bytes with chdir

[dsh0416]

No description provided.

[samuel-williams-shopify]

We cannot use the implementation that changes the current working directory for the process because it's likely to cause unexpected behaviour for any code that's using relative file paths at the same time.

I suggest using a different approach. If the path is too long, construct a temporary socket path, e.g. $tmpdir/$checksum.ipc where $checksum is derived from the original path in a consistent way. Then, use that for bind and connect. In addition, create a symlink from the original path to the temporary socket path. This should be sufficient to have the same visible effects but allows us to use a shorter path for the socket address.

There are some other options like bindat/connectat but these are not standardised system calls unfortunately.