Reviewed this issue in #archlinux and my problem was actually with my system libraries - recent update to harfbuzz broke my freetype2 due to Infinality being no longer supported. Went back to default freetype2 and now I can launch with prefer host libraries on. Closing this bug.
Given how popular Infinality was I would not be surprised to see this issue pop up more once this leaves beta.
Nothing extracted yet.
Your system information
Please describe your issue in as much detail as possible:
CSGO fails to boot on the Steam beta with default variables set. Manually setting STEAM_RUNTIME_PREFER_HOST_LIBRARIES allows the game to start. I don't see anything unusual in the stdout compared to a non-crashing boot but I've uploaded it anyway: https://gist.github.com/d904128f6f310eecc89c61e7b9a47377
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