CONFIG_ARC_DW2_UNWIND is not available for thedefaultarchitecture x86.
Result is shown for architecture arc

Enable DWARF specific kernel stack unwind

modulename: unwind.ko

configname: CONFIG_ARC_DW2_UNWIND

Linux Kernel Configuration
└─>ARC Architecture Configuration
└─>ARC debugging
└─>Enable DWARF specific kernel stack unwind
In linux kernel since version 3.1 (release Date: 2011-10-24)  
Compiles the kernel with DWARF unwind information and can be used
to get stack backtraces.

If you say Y here the resulting kernel image will be slightly larger
but not slower, and it will give very useful debugging information.
If you don't debug the kernel, you can say N, but we may not be able
to solve problems without frame unwind information

source code:
selects
CONFIG_KALLSYMS

depends
CONFIG_ARC_DBG