Let Wine display the correct file name and line numbers for backtraces
Wine currently only supports the symbol formats STABS and DWARF 2, but not the other versions, with STABS providing the most information and being the first choice.
Since we already use the cmake variable DBUS_USE_WINE for running tests under Wine, we also use it to activate the special symbol format.
Closes dbus/dbus/#133 (closed)