make: Entering directory `/opt/qtsdk-2010.05/qt/examples/linguist/hellotr-build-desktop'
g++ -Wl,-rpath,/opt/qtsdk-2010.05/qt/lib -o hellotr main.o -L/opt/qtsdk-2010.05/qt/lib -lQtGui -L/opt/qtsdk-2010.05/qt/lib -L/usr/X11R6/lib -lQtCore -lpthread
/opt/qtsdk-2010.05/qt/lib/libQtGui.so: undefined reference to `FT_Library_SetLcdFilter'
make: Leaving directory `/opt/qtsdk-2010.05/qt/examples/linguist/hellotr-build-desktop'
libQtGui.so 引用了一个 FT_Library_SetLcdFilter函数但是没有找到,请问需要安哪个库?