default or selected kernelversion does not have config value CONFIG_LIB_MEMNEQ.
Result is shown for kernelversion 6.9.9

CONFIG_LIB_MEMNEQ (not configurable)

configname: CONFIG_LIB_MEMNEQ

Linux Kernel Configuration
└─>Library routines
└─>LIB_MEMNEQ
In linux kernel since version 5.2 (release Date: 2019-07-07)