AIX shared library support and GCC PIC libraries

[David Edelsohn]

	My original message only asked about the design, not the
implementation.  I thought that he only okayed the design.  I am uncertain
about what syntax would be best in the implementation and I would
appreciate any guidance before I forge ahead.

	Also, I want to make sure that I did not miss any special care
needed by a specific target, so I wanted to make sure that people with
broad knowledge of a lot of ports were aware of this before I broke
something.  This is a pervasive change in the build process, so I want to
be as careful as possible ... and my name isn't Richad (:^).

Thanks, David