Patches for support of Cray's compiler

[Eric Bavier]

I'm sending two patches that are the beginnings of support for Cray's
compiler in libtool.  I believe this bit of porting will be sufficient
for most uses of libtool at this point, and is of course much better
than the current state.

The first patch is a trivial change to an assumption made in one of
the tests and can certainly be contested.

The second patch contains the heart of the port.  I'd be interested to
know if there are preferable methods for achieving the necessary
behavior, which is hopefully conveyed well enough in the commit
messages and code comments.

I was able to get roughly 166 of the 169 tests to pass.  Some of the
fortran tests required some patches that I am not posting here because
I do not think the solutions are general enough yet.

Comments and questions are certainly welcome.