[texdoc] diagnostics

[Karl Berry]

    Hope it's ok. The point is, viewer are usually launched asynchronously ('xpdf
    foobar.pdf &') so I can't really check the exit status.

Right.  Is good.

    Also, I suppressed the uselessly verbose parts of --debug output so
    that it's only about 200 lines long now. (And now any debug option
    implies --verbose.)

Excellent.  Sounds just right.

    Because evince is in the PATH. If it cannot detect a know desktop
    environment (Gnome, KDE, XFCE) texdoc sequentially checks for known
    viewers in the PATH and picks the first one found. evince happens to
    come before xdvi in this list.

I don't follow that logic.  I think if no desktop environment is found,
texdoc -- being a TeX Live program -- should fall back to xdvi (dviout
on Windows), as the "generic" DVI viewer that is most likely to be
present and working.

    I think the idea behind that was that xdvi is installed by default,
    but not evince, so if evince is installed, it is likely to be a
    conscious choice, so maybe it means the users prefers it...

No, that's not the case.  At least not for me.  What's installed on the
system doesn't really say anything about what a particular user likes.
If I'm actually running under GNOME or whatever, then using the GNOME
viewer makes sense.  But not if I'm in a vanilla X environment.

Thanks,
K