Possibility of adding -aux-directory flag to TeXLive (similar to MikTeX's option)

[Karl Berry]

    The ‘--aux-directory’ is a convenient flag

I'm sorry, but I am just not enthused about supporting this at the
engine level. It seems to me that anything that wants to control where
files end up is better using any of the zillions of front-end scripts
that do or can offer the feature. It seems pretty easy to me for a
script like latexmk to use -output-directory and then mv the final .pdf
(or .dvi) back to the main directory if that's what the user wants. It
is nowhere near as easy or reliable or secure to implement all that in
every engine for every os.

Also sorry, but I'm not convinced by your links that there is a problem
that should be fixed, or that there is a general problem with
\include. Clearly -aux-directory would be a convenience for some users,
but whether the convenience outweighs the complications is another
question. --best, karl.