There are several bugfixes in this update, but the most important one is
to ensure __start_ and __stop_ symbols for linker sets and kernel module
metadata are always emitted in object files:
http://llvm.org/bugs/show_bug.cgi?id=9292
Before this fix, if you compiled kernel modules with clang, they would
not be properly processed by kldxref, and if they had any dependencies,
the kernel would fail to load those. Another problem occurred when
attempting to mount a tmpfs filesystem, which would result in 'operation
not supported by device'.