Log Message:
fix build on Darwin:

- libtool needs -dynamiclib on Darwin to create shared libraries
- don't use libtool to create the static libtclstub.a, do it the same
  way that tcl 8.4 does
- name library libtcl83 (as opposed to libtcl8.3) like other platforms
- remove PLIST unnecessary hack for Darwin shlib name