Change library source toolchain

For a few years, I have been working in a project using Imx6sbc, dey 2.4 distribution. I followed the steps in digi documentation to install qt, qtcreator, yocto, I have buildied my own linux image that It’s working in my Imx6sbc board. I build my app that is a big project but I have a problem with my app and touchscreen, In certainly time when I press the touchscreen the app freezes.
Reading a lot of forums and documentation and debugging the application I think that the problem is in xlib, xlibInput library, that locks the display for some reason. There is a new version of xlib that supposedly fixes this problem.
When I started to use imx6 digi board I had to install a toolchain to cross-compile qt application. I think that this toolchain is pre-compiled and is installed in /opt/dey2.4/. And the xlib library sources are stored in /opt/dey/2.4/sysroot/cortex9hf-neon-dey-linux-gnuabi/usr/src
At first, I thought that only changing the files toolchain sysroot was enough and then compiling with qtcreator I would use the xlib new version but I think that I was wrong.
I think that I have to change the source library files and then re-compile the toolchain but I don’t know how to do It. I think that is with bitbake but I don’t sure how can I do this.
If someone did this before that can I help me.