bug#20629: 25.0.50; Regression: TAGS broken, can't find anything in C++ files.

[Eli Zaretskii]

> Date: Sat, 23 May 2015 17:46:18 +0300
> From: Eli Zaretskii <eliz@gnu.org>
> Cc: 20629@debbugs.gnu.org
> 
> > Date: Sat, 23 May 2015 16:50:11 +0300
> > From: Eli Zaretskii <eliz@gnu.org>
> > Cc: 20629@debbugs.gnu.org
> > 
> > We should try to fix bugs without re-introducing previously solved
> > ones.
> 
> Does the patch below give good results in real-life C++ usage?
> 
> Please also consider whether this change could cause trouble in other
> C++ use cases.  (I've ran the modified version on the etags test
> suite, and didn't spot any problems in the differences with the
> previous results, but I don't consider myself an expert on C++
> syntax.)

I see that etags deliberately produces explicitly named tags of the
form CLASS::MEMBER, whenever it sees a declaration of MEMBER inside a
class declaration of CLASS.  Why is that useful?  It is another
instance that defeats the change which removed tag-symbol-match-p from
the "order" functions used by etags.el when invoked from xref.  Does
anyone see a problem with removing this feature from etags?