./configure fails when creating R 2.15.3

I'm subscribing to R-devel, where may be the proper place to post this
query. Sorry.

I have a reason to create R from the source code. I have a MacBook Pro
running OS X 10.8.2. I've downloaded 'gfortran-4.2.3.pkg' and
installed Fortran.

I downloaded R-2.15.3 and tried to do a "./configure".

The configure fails and the error messages I'm seeing are:

checking for dummy main to link with Fortran 77 libraries... none
checking for Fortran 77 name-mangling scheme... unknown
configure: WARNING: unknown Fortran name-mangling scheme
checking whether gfortran appends underscores to external names... unknown
configure: error: cannot use Fortran

I've read the admin manual.

My Mac system is vanilla,

so I had been hoping that I'd have no
difficulty generating R but unfortunately I was wrong. Can someone
suggest something for me to try?

Thanks.