Fix compilation with -Oodfa

compiler/systems/t_linux.pas

@@ -870,6 +870,7 @@ begin
   MakeSharedLibrary:=false;
   mapstr:='';
   ltostr:='';
+  rpathstr:='';
   if not(cs_link_nolink in current_settings.globalswitches) then
    Message1(exec_i_linking,current_module.sharedlibfilename);
   if (cs_link_smart in current_settings.globalswitches) and