CONFIG_XTENSA_UNALIGNED_USER is not available for thedefaultarchitecture x86.
Result is shown for architecture xtensa

Unaligned memory access in user space

configname: CONFIG_XTENSA_UNALIGNED_USER

Linux Kernel Configuration
└─>Processor type and features
└─>Unaligned memory access in user space
In linux kernel since version 2.6.13 (release Date: 2005-08-28)  
The Xtensa architecture currently does not handle unaligned
memory accesses in hardware but through an exception handler.
Per default, unaligned memory accesses are disabled in user space.

Say Y here to enable unaligned memory access in user space.