question about ns2.1b6 (RENAMED)

["Guo, Liang" <guol@ccs.neu.edu>]

Hi, there:

I got the following error message when compiling the
ns2.1b6 package:

Undefined                       first referenced
 symbol                             in file
_RENAMED                            drop-tail.o

the hint in CHANGES.html is unclear to me, what should
I do to solve this problem? Appreciated.

Guo, Liang.