CONFIG_MACH_MESON8B is not available for thedefaultarchitecture x86.
Result is shown for architecture arm
default or selected kernelversion does not have config value CONFIG_MACH_MESON8B.
Result is shown for kernelversion 6.7-rc3

Amlogic Meson8b SoCs support

configname: CONFIG_MACH_MESON8B

Linux Kernel Configuration
└─>Amlogic Meson SoCs
└─>Amlogic Meson8b SoCs support
In linux kernel since version 4.1 (release Date: 2015-06-21)