[Bug-AUCTeX] Bad interaction with master file and dtx files.

[David Kastrup]

Hi, I've seen somebody edit a file in docTeX-mode with a master file
that is called something.tex.

When he runs C-c C-c RET, LaTeX tries to compile something.dtx
instead.

That is nonsense.  It happens by docTeX-default-extension being copied
to TeX-default-extension.

I don't know the exact role of TeX-default-extension, but one of its
functions appears to signify something which _can_ be stripped from a
file name without changing its meaning to TeX.  In this function,
nothing but a hard-coded ".tex" makes sense.

-- 
David Kastrup, Kriemhildstr. 15, 44793 Bochum