comctl: allow label edit only if treeview style allows editing

[Dan Kegel]

> I stopped doing
> make test on my machine some time ago

Bad developer, no donut :-)

> , when I found out that some
> tests do consistently fail on my machine (clean prefix or not), and
> others consistently hang, thus preventing make test -k.

I had the same problem, and wrote a little script to skip the bad tests.
It was written for buildbot, but can be run standalone.
Try downloading
http://winezeug.googlecode.com/svn/trunk/buildbot/dotests.sh
and
http://winezeug.googlecode.com/svn/trunk/buildbot/dotests_blacklist.txt
then run
  sh dotests.sh goodtests
That will skip all the tests known to hang or fail.  (The list might be
a bit out of date, but it's easy to add new tests to the blacklist.)

> I don't install wine-gecko, maybe that's the reason.

Run https://winetricks.googlecode.com/svn/trunk/src/install-gecko.sh
then you'll never have to install it again.  (Until it's updated, anyway.)
- Dan