After a compilation trying of a sockets example code (https://goo.gl/ddDE8u), some errors gone.. and among them, a the pointer casting related one that I cannot solve by myself.
It looks to me like the root of your problem is that you are trying to compile an example for glibmm master/next, but while linking to the glibmm-2.4 ABI... That won't work. In glibmm next, Glib::RefPtr is now an std::shared_ptr, hence the std:: casts in the example code, but that will not work in glibmm-2.4 where RefPtr is a completely custom class.
Presumably you should look for the corresponding example code in the right branch of glibmm, then your errors will all vanish.
