QtNetwork fails to compile on top of public Belle SDK 0.6

qnetworkinterface_symbian.cpp has dependency to in_iface.h which is not part of public Belle SDK 0.6

"/home/liangqi/qt/work/src/network/kernel/qnetworkinterface_symbian.cpp", line 51: Error: #5: cannot open source input file "in_iface.h": No such file or directory
#include <in_iface.h>
^
make[1]: *** [.obj/debug-shared/qnetworkinterface_symbian.o] Error 1
make[1]: Leaving directory `/home/liangqi/build/s3-armcc/src/network'
make: *** [sub-network-make_default] Error 2