Comment 6 for bug 1510299

Hmm… ok. Now there's another error message coming from the linker.

I think there's a general problem compiling gtkmm applications on your system.

Let's do a simple test.
Replace the contents of the following files:

CMakeLists.txt
######################################
project(GrubCustomizer)
cmake_minimum_required(VERSION 2.6.2) # may be lower

find_package(PkgConfig)

pkg_check_modules(GTKMM gtkmm-3.0)
pkg_check_modules(GTHREAD gthread-2.0)
pkg_check_modules(OPENSSL openssl)
pkg_check_modules(LIBARCHIVE libarchive)

link_directories(
    ${GTKMM_LIBRARY_DIRS} ${OPENSSL_LIBRARY_DIRS} ${LIBARCHIVE_LIBRARY_DIRS} )

include_directories(
    ${GTKMM_INCLUDE_DIRS} )

add_executable(gtk-testapp
 src/main/gtk-client.cpp
)

target_link_libraries(gtk-testapp
    ${GTKMM_LIBRARIES} ${GTHREAD_LIBRARIES} ${OPENSSL_LIBRARIES} ${LIBARCHIVE_LIBRARIES})
######################################

src/main/gtk-client.cpp
######################################
#include <gtkmm.h>

int main(int argc, char** argv)
{
 Gtk::Main app(argc, argv);

 Gtk::Window win;

 win.set_title("Testapp");
 win.set_default_size(400, 300);

 Gtk::Label lbl(Glib::ustring("Testapp"));

 win.add(lbl);
 win.show_all();

 app.run(win);
}
######################################

Then compile it.