LaTeX engine temporary file naming and parallel build system interoperability

Determine whether LaTeX engines should automatically generate unique temporary file names to reduce latency when many compilations run concurrently.

The current default writes auxiliary files (.aux, .log, .fls) with predictable names in the working directory, causing I/O contention that grows with the number of parallel jobs. While flags such as -output-directory and -aux-directory can isolate files, they require explicit configuration and must be respected by downstream tools like bibtex or makeglossaries, which adds complexity to build systems.

Should the engines embed a process‑specific identifier (e.g., PID or UUID) in auxiliary file names by default? What are the consequences for incremental builds, cache invalidation, and reproducibility? How would this behavior interact with existing -output-directory and -aux-directory options?