Determining install prefix of my program

[Галымжан Кожаев <kozhayev gmail com>]

I have only one problem: how can I determine install prefix of my
program (e.g./usr/local/), does gtkmm have such functions ? The
program must correctly determine it in order to load program images,
gladefiles and etc. The program uses gtkmm 2.16 and glibmm 2.20, also
CMake 2.6 used for building project.