[patch] libstdc++/56785 reduce space overhead of nested tuples

[Marc Glisse]

Hello,

just checking that I understand how it works. std::tuple did not exist in 
C++03, so its ABI was not fixed, and you don't need to set abi_tag on it 
and on all the tuple users in libstdc++, which are also new in C++11.

What about std::rotate in a different patch though? As I understand it, 
changing the return type does not affect the mangling, and if we use the 
new function (and its return value) and link with older code that has the 
old function, if the linker picks the old function, bad things may happen, 
no?

-- 
Marc Glisse