The SquashFS creation is not deterministic

This applies both to the SquashFS in the ISO and the one in IUKs. I’m told that -no-fragments should fix it, but:

• this might make the compression rate worse;
• one might need to pass a fixed value to -processors too.

Contact info of the people investigating this: lynxis@fe80.eu and hanno@hboeck.de.

Parent Task: #5630 (closed)

Related issues

• Related to #11974 (closed)
• Blocked by #11966 (closed)

Original created by @intrigeri on 12032 (Redmine)