undefined versioned symbol name

[bryanh at giraffe-data dot com (Bryan Henderson)]

I stumbled across a weird behavior that I'm trying to figure out.
If I knew anything about versioned symbols, it might make sense.

I do

  ld -shared /usr/lib/libc.so strdup.o

strdup.o defines the symbol "strdup", which is obviously defined in 
libc.so as well.  libc.so is glibc 2.1.3.

This produces the error message:

  ld: a.out: undefined versioned symbol name strdup@@GLIBC_2.0

Why?  What is it telling me?

This is followed by the message

  ld: failed to set dynamic section sizes: Bad value

which kind of makes it sound like an internal failure.  But I'm not
jumping to any conclusions, since I don't know how versioned symbols
work at all.

This is GNU ld 2.10.1.

-- 
Bryan Henderson                                    Phone 415-505-3367
San Jose, California