Add versioning information to symbols.

Bug: http://b/28178111
Change-Id: I46bf95accd819f4521afb1173d8badcc5e9df31c
diff --git a/libc/include/bits/lockf.h b/libc/include/bits/lockf.h
index a0ba19d..655514d 100644
--- a/libc/include/bits/lockf.h
+++ b/libc/include/bits/lockf.h
@@ -42,9 +42,9 @@
 #if defined(__USE_FILE_OFFSET64)
 int lockf(int, int, off_t) __RENAME(lockf64);
 #else
-int lockf(int, int, off_t);
+int lockf(int, int, off_t) __INTRODUCED_IN(24);
 #endif
-int lockf64(int, int, off64_t);
+int lockf64(int, int, off64_t) __INTRODUCED_IN(24);
 
 __END_DECLS