Re-submit "Name function arguments in libc headers for Studio."

This reverts commit 9af9120091ceb96641d7c6c645fabad96db4bc0d (a revert
of 079bff4fa52b0c3c76057451cc9cdecf1827fce0), now the versioner bug is
fixed.

Bug: http://b/64613623 # header bug
Bug: http://b/64802958 # versioner bug
Change-Id: I1cb9d7832d4b3aecdc57a9285e2291443e59d02d
diff --git a/libc/include/sys/file.h b/libc/include/sys/file.h
index f414d34..a420021 100644
--- a/libc/include/sys/file.h
+++ b/libc/include/sys/file.h
@@ -36,8 +36,8 @@
 
 __BEGIN_DECLS
 
-int flock(int, int);
+int flock(int __fd, int __op);
 
 __END_DECLS
 
-#endif /* _SYS_FILE_H_ */
+#endif