Bikeshed discussion on name of library file for Filesystem TS

[Jonathan Wakely <jwakely dot gcc at gmail dot com>]

I'm going to commit <experimental/filesystem> soon, and as previously
explained, all the new code is in a separate archive, not in
libstdc++.so.

I think I called that archive libstdc++fs.a but it might be a good
idea to discuss better names.

* Should the name have libstdc++ or GNU in it somewhere, to
distinguish our library from another implementation's? Or would it be
better if different implementations used the same name, so users'
makefiles are simpler?

* Should the archive name indicate the TS contents are "experimental"
(as the namespace and include path already do)?

Some options include:

libstdc++file.a
libc++file.a
libg++file.a
libstdexpfile.a
libexpfile.a
libfilec++.a

Or any of the above with "fs" or "filesystem" instead of "file".

Or there's the accurate-but-not-very-exciting name, libts18822.a,
since the document is ISO/IEC TS 18822.

I'm hoping there's a really good name that I just haven't thought of!