usr.bin/vi/include/file.h

/*
 * If we're doing flock(2) emulation, we need to get the LOCK_* #defines.
 * This stub <sys/file.h> includes the real one, and, if they're not in
 * it, we #define them here.
 */

#include </usr/include/sys/file.h>

#ifndef LOCK_SH
/* lock operations for flock(2) */
#define LOCK_SH         0x01            /* shared file lock */
#define LOCK_EX         0x02            /* exclusive file lock */
#define LOCK_NB         0x04            /* don't block when locking */
#define LOCK_UN         0x08            /* unlock file */
#endif