Feature: Add Open File Descriptor (OFD) Locking constants for 64-bit-offset programs.
Reason: OFD locks are superior to per-process locks for some applications.
Result: 64-bit-offset programs[*] will be able to use the F_OFD_* constants in system calls, although they'll still need to detect if the kernel supports those operations. Programs which use 32-bit file offsets will not have access to these constants, as the RHEL 7 ABI does not support translating them.
[*] Those that #define _FILE_OFFSET_BITS 64