Thunderbird unable to connect to Sync Clippings Helper on macOS

[aecreations]

On macOS, Clippings for Firefox can connect to the Sync Clippings Helper app without issue. But Clippings for Thunderbird is unable to connect to the native messaging app.

The cause was narrowed down to the location of the native messaging manifest. On macOS, it needs to be placed in /Library/Application Support/Mozilla/NativeMessagingHosts.

To work around this Thunderbird limitation, the Sync Clippings Helper installer package and shell script needs to be modified to write the native messaging manifest to the globally-visible file location.

This issue is NOT occurring on Linux (verified on Ubuntu 20.04).

[aecreations]

The setup script is updated for both macOS and Linux to create the native messaging manifest in the globally-visible file location; for Linux this is /usr/lib/mozilla/native-messaging-hosts.