initial, prototype modifications to permit compilation of local libraries as static...

initial, prototype modifications to permit compilation of local libraries as static libs. required a "fix" to libs/pbd/debug.cc to even get the program up and running, and still does not work due to issues with boost::shared_ptr::enable_shared_from_this. controlled by configure-time --internal-{static,shared}-libs, set to shared by default (as has been the case for years)