Cross-compile error: PKG_CONFIG_SYSROOT_DIR

[Charlie_Y]

The referenced article: http://qt-project.org/wiki/RaspberryPi_Beginners_guide

When I compile the qtbase as follow, I have a problem.

@./configure -opengl es2 -device linux-rasp-pi-g++ -device-option CROSS_COMPILE=~/opt/tools-master/arm-bcm2708/gcc-linaro-arm-linux-gnueabihf-raspbian/bin/arm-linux-gnueabihf- -sysroot /mnt/rasp-pi-rootfs -opensource -confirm-license -optimized-qmake -reduce-exports -release -make libs -prefix /usr/local/qt5pi@

The error is:
@Running configuration tests...
Note: PKG_CONFIG_LIBDIR automatically set to /mnt/rasp-pi-rootfs/usr/lib/pkgconfig:/mnt/rasp-pi-rootfs/usr/share/pkgconfig:/mnt/rasp-pi-rootfs/usr/lib/arm-linux-gnueabihf/pkgconfig
Note: PKG_CONFIG_SYSROOT_DIR automatically set to /mnt/rasp-pi-rootfs
The test for linking against libxcb and support libraries failed!
You might need to install dependency packages, or pass -qt-xcb.
See src/plugins/platforms/xcb/README.@

I enter the command sudo apt-get install libxcb*, but this problem still exists.

[dheerendra]

Did you try giving -qt-xcb to build configuration ?

[Charlie_Y]

[quote author="Dheerendra" date="1410870859"]Did you try giving -qt-xcb to build configuration ?[/quote]
I try it and now I can make install it. Why does this problem exist? Will this problem make the application cross-compiling error on Raspberry Pi?