I have tried to build QT from source, but find it does not build the libqxcb.so library. The version that gets downloaded as part of the plugins/platforms directory is not compatible with my system, as it appears to have been built against newer versions of libc.so than is currently on my system. Therefore, I would like to rebuild libgxcd.so on my system, but can't figure out how to do that. I tried to add the -qt-xcb flag to the configure call, but get the following error as a result: "ERROR: Feature 'xcb' was enabled, but the pre-condition 'features.thread && features.xkbcommon && libs.xcb' failed." I do have libxcb.so.1.1.0 on my system (from libxcd-1.12-4 package). It appears to me that the source for this library is included in the Src/qtbase/src/plugins/platforms/xcb folder. But I don't know how to get this to build.