SOLUTION: This is a Unity 5 issue, they are wrongly assuming that everyone uses pulseaudio. There's a link further down in this thread to the KSP bug tracker, where someone posted a 'pulsenomore' tool as a workaround. This tells Unity to stop looking for pulseaudio, and stops the segfaults on launch. Audio works, the game launches, and everything runs great.
I also ran into the 'empty menus' issue, I've set my resolution to 1363x768 instead of 1366 as another workaround. Other resolutions lead to terrible font rendering - you can use the AnyRes mod to quickly figure out a resolution that works for you.
KSP x64 on Linux crashes way less often than it does on Windows. Thanks to Sal_Vager for helping to resolve this!
Original post -
64-bit Arch Linux, KSP 1.1.2, build id 01260. Clean installation, no Steam.
All I get upon launch is a black screen, and then nothing - crash to desktop.
32-bit KSP launches and loads, but there is no sound (as expected with 32-bit) and menus are empty.
Here is the output when running "LC_ALL=C KSP.x86_64" from a terminal http://hastebin.com/a helohulac.sql
Here is my Player.log; no KSP.log is created when running the 64-bit executable; this is the most useful of the logs http://hastebin.com/elicoyufaj.md
Got a SIGSEGV while executing native code. This usually indicates a fatal error in the mono runtime or one of the native libraries used by your application.
...
FMOD failed to get number of drivers ... An error occured that wasn't supposed to. Contact support.
...
The referenced script on this Behaviour is missing!
(Filename: Line: 1649)
The referenced script on this Behaviour is missing!
(Filename: Line: 1649)
The referenced script on this Behaviour is missing!
(Filename: Line: 1649)
...etc ad nauseum...