[patch] Fix libstdc++ build for Android

[Jonathan Wakely]

On 02/06/17 10:37 +0200, Eric Botcazou wrote:
>Hi,
>
>libstdc++-v3 already contains support but doesn't build for Android.  Now GDB
>has switched to C++, which means that you need a C++ cross-build for GDBserver
>in order to debug a program on the target.
>
>Tested on x86_64-suse-linux and arm-linux-androideab, OK for mainline?

The libstdc++/src/filesystem/dir.cc change is OK.

I'll probably backport that too (as I tend to keep the filesystem
sources in sync on the branches).