discussion seeked for c++ variants in USE_LANGUAGES

[Richard PALO <richard.palo%free.fr@localhost>]

Not finding much discussion about c++ variants in USE_LANGUAGES, I'd 
like to open this topic with a proposal to add 'c++0x', 'c++11', 'c++1y' 
and probably very soon 'c++14' where the default c++ (in gcc at least) 
is c++98 plus extensions (aka gnu++98.

http://www.netbsd.org/~richard/lang_c++.patch

I've tinkered mostly with g++ but clang seems straight forward.

Initial observations:
Currently when 'c99' is set in USE_LANGUAGES, it is actually 'gnu99' 
that is set for 'std=' (for gcc). I followed this usage in the prototype 
for the above c++ variants.

Also, many pkgsrc Makefiles use, for example :
"USE_LANGUAGES+= c99 c++"
This may be okay for clang, but probably a message or some logic that 
g++ use minimally 'c++0x' or 'c++11' is at hand.

While I notice that 'c11' hasn't been added, I wonder if adding all 
these variants is really necessary (maybe only 'c++11' and 'c++14')
again, not so difficult for clang, but there are a lot of gcc versions 
out there... not to mention sunpro or others.
Also, I guess I left out (on purpose) c++03....

The purpose of this is for simplicity in the vast majority of the pkgsrc 
Makefiles... not having any c++ variants certainly does not simplify things.