Darwin: really fix -Xg for DWARF4

compiler/options.pas

@@ -3961,7 +3961,7 @@ begin
     end;
 {$endif i8086_link_intern_debuginfo}
 
-  if (paratargetdbg in [dbg_dwarf2,dbg_dwarf3]) and
+  if (paratargetdbg in [dbg_dwarf2,dbg_dwarf3,dbg_dwarf4]) and
      not(target_info.system in (systems_darwin+[system_i8086_msdos,system_i8086_embedded])) then
     begin
       { smartlink creation does not yet work with DWARF

compiler/systems/t_darwin.pas

@@ -686,7 +686,7 @@ implementation
       { create dsym file? }
       extdbgbinstr:='';
       extdbgcmdstr:='';
-      if (target_dbg.id in [dbg_dwarf2,dbg_dwarf3]) and
+      if (target_dbg.id in [dbg_dwarf2,dbg_dwarf3,dbg_dwarf4]) and
          (cs_link_separate_dbg_file in current_settings.globalswitches) then
         begin
           extdbgbinstr:=FindUtil(utilsprefix+'dsymutil');