From Ubuntu 11.10 (gcc 4.6.1) the libs linking order now matters, so we have to link gtk and glade at the end of the call to gcc:
echo linking...
gcc $1.o -o$1 -L./../lib -L./../../harbour/lib pkg-config --libs libgnomeprintui-2.2 -Wl,--start-group -lfive -lfivec -lhbcommon -lhbvm -lhbrtl -lhbrdd -lhbmacro -lhblang -lhbcpage -lhbpp -lhbcplr -lrddntx -lrddcdx -lrddfpt -lhbsix -lhbusrrdd -lhbct -lgttrm -lhbdebug -lm -lgpm -lncurses pkg-config --libs gtk+-2.0 pkg-config --libs libglade-2.0 -Wl,--end-group
With these changes, it is working fine! 