[Bug c++/49107] [C++0x][4.7 Regression] incomplete type regression with std::pair

[redi at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=49107

--- Comment #14 from Jonathan Wakely <redi at gcc dot gnu.org> 2011-06-04 12:27:50 UTC ---
(In reply to comment #9)
> But doing this breaks auto_ptr.  And v3 future as well, for some reason.

I can take care of any necessary changes to future if you let me know what
breaks (or let me know what to change in the FE to reproduce the breakage)