i can confirm in my case this is all related to the glibc static TLS loading.
loading libGL with LD_PRELOAD fixes only part of the issue,
if you run UE4Editor with ‘LIBGL_DEBUG=verbose’ in addition to the LD_PRELOAD=/usr/lib/fglrx/libGL.so.1, you might find its having trouble loading something else.
without LIBGL_DEBUG=verbose, there is no information in the terminal that indicates anything else has failed.
In my case it was also unable to load fglrx_dri.so…
you can probably fix this by recompiling glibc with bigger DTV_SURPLUS or in my case for testing. I simply launched the editor with the following…
LD_PRELOAD=“/usr/lib64/xorg/modules/dri/fglrx_dri.so /usr/lib/fglrx/libGL.so.1” ./Engine/Binaries/Linux/UE4Editor
good luck…