[C++ Patch, 4.8] Backport fix for c++/54537 to FSF 4.8

[Peter Bergner]

On Fri, 2014-03-21 at 11:30 -0500, Peter Bergner wrote:
> The following patch has lived on mainline for 6 months and has
> not generated any issues there.  We've also been using it on
> our 4.8 based IBM branch with no problems either, so I'd like to
> ask for permission to backport this fix to the FSF 4.8 branch.
> This will bring GCC into compliance with CLANG and the XL C++
> compilers with respect to this bug.  I know the XL C++ compiler
> specifically will not accept the definition in the tr1/cmath header
> file, therefore it is not able to compile any program that uses
> that header.
> 
> Since there are a few 4.8 based distro compilers coming, I'd like to
> fix this in the FSF branch so they'll all get the fix automatically.
> Ok for the FSF 4.8 branch once my bootstrap and regtesting are
> complete (using powerpc64-linux)?

FYI, this just completed bootstrap and regtesting with no regressions.

Ok for the FSF 4.8 branch?

Peter