Enable Mandatory file locking

configname: CONFIG_MANDATORY_FILE_LOCKING

Linux Kernel Configuration
└─>File systems
└─>Enable Mandatory file locking
In linux kernel since version 4.1 (release Date: 2015-06-21)  
This option enables files appropriately marked files on appropriely
mounted filesystems to support mandatory locking.

To the best of my knowledge this is dead code that no one cares about.