TeX-master and TeX-output-master

[Tohiko Looka]

Hello,

I usually compile my latex files with pdflatex and use the argument
`--output-directory` to have all output files saved inside a hidden
`build` subdirectory (I also have a command to copy out the pdf output
or attach it in an email... etc).
This clearly breaks auctex, because the master tex file is in a
different directory from the required output files (log, aux and pdf).

At the moment, I hacked together a solution by advising the function
TeX-master-file to return a fake master which is inside my output
directory. This works most of the time, but I did have to rewrite
functions which require the correct path to the tex master file (like
`TeX-synctex-output-page`).

I was wondering if there's interest in extending auctex to have two
properties: TeX-master and TeX-output-master. Then the correct master
of the two is used in the hundred places or so in auctex where
TeX-master-file is currently always used.

-- Tohiko