How much does libstdc++ GPL exception last

[Chris Jefferson]

If I take headers from the libstdc++-v3 project, hack them up a bit,
and then include them in my own project will they keep the GPL
exception (ie the rest of the project doesn't have to be under the
GPL)?

I want to do this so I can distribute a) bits of TR1 and b) bits of
the v7 <algorithm> changes I made with my project. I intend to pop
them into their own namespace.

Apologises for the legal question, I understand if the answer is "we
don't really know".

Chris