Problem building shared libraries on OS X

[Wade Williams]

I'm trying to build gmp-2.5.1 on Mac OS X, 10.4.6.  Previous versions  
of gmp have built without difficulty.

However, in this version, I cannot get shared libraries to build.

I run:

./configure --enable-shared  (which should be the default anyhow)

and I get:

checking whether stripping libraries is possible... yes
checking if libtool supports shared libraries... no
checking whether to build shared libraries... no
checking whether to build static libraries... yes

I suspect this may be because of a missing or incorrect flag passed  
to libtool.  libtool can create shared libraries on OS X.

Any thoughts on how to debug this?  Unfortunately, I am not terribly  
autoconf savvy, but I'm willing to work with anyone on debugging the  
issue.

Thanks,

Wade