gtkgl?!

libtool: link: gcc -g -O2 -pthread -I/usr/include/gtk-2.0 -I/usr/lib/gtk-2.0/include -I/usr/include/pango-1.0 -I/usr/include/atk-1.0 -I/usr/include/cairo -I/usr/include/pixman-1 -I/usr/include/libpng16 -I/usr/include/gdk-pixbuf-2.0 -I/usr/include/libpng16 -I/usr/include/pango-1.0 -I/usr/include/harfbuzz -I/usr/include/pango-1.0 -I/usr/include/freetype2 -I/usr/include/glib-2.0 -I/usr/lib/glib-2.0/include -Wall -o .libs/simple simple.o -Wl,--export-dynamic -pthread  ../gtkgl/.libs/libgtkgl-2.0.so /usr/lib/libgtk-x11-2.0.so /usr/lib/libgdk-x11-2.0.so /usr/lib/libpangocairo-1.0.so /usr/lib/libatk-1.0.so /usr/lib/libcairo.so /usr/lib/libgdk_pixbuf-2.0.so /usr/lib/libgio-2.0.so /usr/lib/libpangoft2-1.0.so /usr/lib/libpango-1.0.so /usr/lib/libgobject-2.0.so /usr/lib/libfreetype.so /usr/lib/libfontconfig.so /usr/lib/libgmodule-2.0.so /usr/lib/libglib-2.0.so /usr/lib/libGLU.so /usr/lib/libGL.so -pthread
libtool: link: gcc -g -O2 -pthread -I/usr/include/gtk-2.0 -I/usr/lib/gtk-2.0/include -I/usr/include/pango-1.0 -I/usr/include/atk-1.0 -I/usr/include/cairo -I/usr/include/pixman-1 -I/usr/include/libpng16 -I/usr/include/gdk-pixbuf-2.0 -I/usr/include/libpng16 -I/usr/include/pango-1.0 -I/usr/include/harfbuzz -I/usr/include/pango-1.0 -I/usr/include/freetype2 -I/usr/include/glib-2.0 -I/usr/lib/glib-2.0/include -Wall -o .libs/zktor zktor.o -Wl,--export-dynamic -pthread  ../gtkgl/.libs/libgtkgl-2.0.so /usr/lib/libgtk-x11-2.0.so /usr/lib/libgdk-x11-2.0.so /usr/lib/libpangocairo-1.0.so /usr/lib/libatk-1.0.so /usr/lib/libcairo.so /usr/lib/libgdk_pixbuf-2.0.so /usr/lib/libgio-2.0.so /usr/lib/libpangoft2-1.0.so /usr/lib/libpango-1.0.so /usr/lib/libgobject-2.0.so /usr/lib/libfreetype.so /usr/lib/libfontconfig.so /usr/lib/libgmodule-2.0.so /usr/lib/libglib-2.0.so /usr/lib/libGLU.so /usr/lib/libGL.so -pthread
/usr/bin/ld: zktor.o: undefined reference to symbol 'atan2@@GLIBC_2.0'
/usr/bin/ld: note: 'atan2@@GLIBC_2.0' is defined in DSO /lib/libm.so.6 so try adding it to the linker command line
/lib/libm.so.6: could not read symbols: Invalid operation
collect2: error: ld returned 1 exit status
make[2]: *** [zktor] Error 1
make[2]: *** Waiting for unfinished jobs....
make[2]: Leaving directory `/sources/gtkglarea-2.0.1/examples'
make[1]: *** [all-recursive] Error 1
make[1]: Leaving directory `/sources/gtkglarea-2.0.1'
make: *** [all] Error 2