PATCH RFA: Permit backward/hash_map with -Wdeprecated

[Paolo Carlini]

Hi,

> Bootstrapped and ran libstdc++ testsuite on i686-pc-linux-gnu.  OK  
> for mainline?

I'm away from my primary development machine and cannot check the  
whole logic behind those macros, but first blush I'm not ok with the  
patch. *When* are we going to warn, with the patch applied? Because  
morally this stuff *is* deprecated, and that is already a concession.  
If essentially we are going to never warn, then let's move back this  
stuff to ext/, seems much cleaner to me. I have no problem with the  
other maintainers overruling me about these issues, but really  
personally I'm not confortable with extending the life of this old  
code, simply we don't have the manpower to care about legacy stuff,  
with all the work ahead of us for C++1x!

Paolo