[PATCH] Fix libstdc++/6503

[Gabriel Dos Reis]

Paolo Carlini <pcarlini@unitus.it> writes:

| Gabriel Dos Reis wrote:
| 
| >Just curious: Isn't turning a member function into a non-member
| >function an ABI change?
| >
| Gaby, I'm really eager to understand more about this...
| 
| My naive understanding of such matters is based on object files and 
| linking with libraries. If there are no instantiations  present in the 
| libstdc++.so binary (this I have verified troughly) how could the whole 
| break as an effect of moving the members??

Well, my remark was based on your description:

   I have fixed this PR according to Scott Meyers' guideline about 
   comparison operators as non-member functions (Effective STL, 119): now 
   all the _Deque_iterator comparison operators are non-members

and the removal of member comparaison operators.  So I wanted to know
whether that isn't an ABI change.

-- Gaby