Missing explicit instantiation for format_float<double> and <long double>

[Smjert]

I've compiled fmt(7ce7def) as a shared library with Clang 3.9.0, when i include the fmt/format.h header in my project clang warns about format_float for double and long double not being explicitly instantiated.

Now my guess is that since it is explicitly instantiated in the format.cc, but where i'm using the function is not the same TU, it needs to be either explicitly instantiated again (by me) or even better format.h should contain an extern template declaration (i did that and the warning went away), because the template is effectively instantiated "somewhere else".