Fix services menu empty on OSX 1.6+.

Fix services menu empty on OSX 1.6+.

* nsfns.m (Fx_open_connection): Remove NSStringPboardType from
ns_return_types.
(Fns_list_services): Just return Qnil on 10.6, code not working there.

* nsmenu.m (ns_update_menubar): Remove useless setDelegate call
on svcsMenu.

* nsselect.m (ns_get_local_selection): Change to extern (Bug#8842).

* nsterm.h (MAC_OS_X_VERSION_10_6): Define here instead of nsterm.m.
(ns_get_local_selection): Declare.

* nsterm.m (QUTF8_STRING): Declare.
(initFrameFromEmacs): Call registerServicesMenuSendTypes.
(validRequestorForSendType): Return type is (id).
Change indexOfObjectIdenticalTo to indexOfObject.
Check if we have local selection before returning self (Bug#8842).
(writeSelectionToPasteboard): Put local selection into paste board
if we have a local selection (Bug#8842).
(syms_of_nsterm): DEFSYM QUTF8_STRING.