Heads up: glibmm/gtkmm now requires -std=c++11

[Kevin Kofler]

Kalev Lember wrote:
> The fix is simple: make sure -std=c++11 is passed to the compiler.

The default is gnu++98, so if you were using the default, you probably want 
gnu++11 instead. c++11 is strict C++11 without GNU extensions.

        Kevin Kofler