AFAIK, /lib and /usr/lib don't go into /etc/ld.so.conf [...not needed as those paths are hardcoded into the linker itself ...is my guess]
In fact I tried that in the past and it introduced new bugs [...YMMV], so if it didn't work anyway, you may be better off taking it out. [...if you do, run #ldconfig again afterwards]
Use the rpm tools to first see what pkg supplies libGLcore,
...see if the right pkg is already installed,
#rpm -qa | grep <pkg>
...and install, if required,
If rpm -qa shows the <pkg> as already installed, it could mean you don't have the right version installed to satisfy the new app's dependency.