CONFIG_RTC_MC146818_LIB (not configurable)

modulename: rtc-mc146818-lib.ko

configname: CONFIG_RTC_MC146818_LIB

Linux Kernel Configuration
└─>Device Drivers
└─>RTC_MC146818_LIB
In linux kernel since version 4.1 (release Date: 2015-06-21)  
source code:
drivers/rtc/rtc-mc146818-lib.c
selects
CONFIG_RTC_LIB