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

[Eli Zaretskii]

> Cc: 20629@debbugs.gnu.org
> From: Dmitry Gutov <dgutov@yandex.ru>
> Date: Tue, 26 May 2015 13:16:15 +0300
> 
> One direction would be to add `:' to NONAM, so that a method name would 
> implicitly match a qualified tag as well. Not sure if it will be a 
> problem in some languages (but in, say, Elisp `:' can be a part of an 
> identifier).

That'd mean either some very invasive change in the insane state
machine that runs C_entries, or, more likely, throwing it away and
re-writing it in a very different way.  I don't volunteer.

> Another - to make etags-tags-completion-table include both the pattern 
> and the explicit tagname in the returned obarray.

Yes, I thought about this as well.  I think this is our best bet, and
shouldn't be too hard, as we already do similar things elsewhere.
Patches from completion experts are welcome.