Name function arguments in libc headers for Studio.

Second batch of headers...

Bug: http://b/64613623
Test: builds
Change-Id: I8eef043dbf32afee8ff814e9d005f46aee8fa21f
diff --git a/libc/include/sys/ipc.h b/libc/include/sys/ipc.h
index 3d6c45f..dee7c8a 100644
--- a/libc/include/sys/ipc.h
+++ b/libc/include/sys/ipc.h
@@ -42,8 +42,8 @@
 
 __BEGIN_DECLS
 
-key_t ftok(const char* path, int id);
+key_t ftok(const char* __path, int __id);
 
 __END_DECLS
 
-#endif /* _SYS_IPC_H */
+#endif