[Bug c++/57390] Fixed point types on AVR are not available in C++ mode

[pinskia at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=57390

--- Comment #1 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
There is no way to enable it for C++ because the extension has not been
designed to how it would interact with templates and such.

See the thread at http://gcc.gnu.org/ml/gcc/2011-11/msg00124.html for more
info.