PATCH: PR other/17783: Top level configure doesn't support shared libraries enabled by default

[Joe Buck]

I wrote:

> I just started a test of HJ's patch, applied to the first release
> candidate you sent out, on a Red Hat AW2.1 ia64 system, which appears
> to be a system without system libunwind.  This was the one I reported
> failing before.

The compiler has built and passed make compare; it is currently building
the Java library.  So at least for RHAW 2.1/ia64, HJ's patch solves
the problem.