Cleanup patches from Greg Stein:

* in import.c, #ifdef out references to dynamic loading based on
  HAVE_DYNAMIC_LOADING

* clean out the platform-specific crud from importdl.c.
  [ maybe fold this function into import.c and drop the importdl.c file? Greg.]

* change GetDynLoadFunc's "funcname" parameter to "shortname". change
  "name" to "fqname" for clarification.

* each GetDynLoadFunc now creates its own funcname value.

  WARNING: as I mentioned previously, we may run into an issue with a
  missing "_" on some platforms. Testing will show this pretty quickly,
  however.

* move pathname munging into dynload_shlib.c