+#ifndef LOCK_SH
+/* Operations for the 'flock' call (same as Linux kernel constants). */
+# define LOCK_SH 1 /* Shared lock. */
+# define LOCK_EX 2 /* Exclusive lock. */
+# define LOCK_UN 8 /* Unlock. */
+
+/* Can be OR'd in to one of the above. */
+# define LOCK_NB 4 /* Don't block when locking. */
+#endif
+
+/* The definition of _GL_WARN_ON_USE is copied here. */