Comment 19 for bug 168658

r11522 breaks building with GTK3:

  CXX ui/dialog/font-substitution.o
../../src/ui/dialog/font-substitution.cpp: In member function ‘void Inkscape::UI::Dialog::FontSubstitution::show(Glib::ustring, GSList*)’:
../../src/ui/dialog/font-substitution.cpp:94: error: ‘CheckButton’ is not a member of ‘Gtk’
../../src/ui/dialog/font-substitution.cpp:94: error: ‘cbSelect’ was not declared in this scope
../../src/ui/dialog/font-substitution.cpp:94: error: expected type-specifier
../../src/ui/dialog/font-substitution.cpp:94: error: expected `;'
../../src/ui/dialog/font-substitution.cpp:99: error: ‘CheckButton’ is not a member of ‘Gtk’
../../src/ui/dialog/font-substitution.cpp:99: error: ‘cbWarning’ was not declared in this scope
../../src/ui/dialog/font-substitution.cpp:99: error: expected type-specifier
../../src/ui/dialog/font-substitution.cpp:99: error: expected `;'
../../src/ui/dialog/font-substitution.cpp:104: error: invalid conversion from ‘Gtk::Box*’ to ‘Gtk::VBox*’
make[3]: *** [ui/dialog/font-substitution.o] Error 1
make[2]: *** [all] Error 2
make[1]: *** [all-recursive] Error 1
make: *** [all] Error 2