CONFIG_EXPOLINE_EXTERN is not available for thedefaultarchitecture x86.
Result is shown for architecture s390

Generate expolines as extern functions.

modulename: expoline.ko

configname: CONFIG_EXPOLINE_EXTERN

Linux Kernel Configuration
└─>Processor type and features
└─>Generate expolines as extern functions.
In linux kernel since version 4.14.326 (release Date: 2023-09-23)  
This option is required for some tooling like kpatch. The kernel is
compiled with -mindirect-branch=thunk-extern and requires a newer
compiler.

If unsure, say N.

source code:
depends
CONFIG_CC_IS_GCC
CONFIG_EXPOLINE
CONFIG_GCC_VERSIONCONFIG_110200
CONFIG_success