For our lldb customizations, instead of commenting out lines, use #ifdef LLDB_ENABLE_ALL / #endif preprocess directives instead, so our diffs against upstream only consist of added lines. (Note that upstream has largely reshuffled the way optional lldb plugins are handled, so we need a lot less of these #ifdefs. However, not all of them can be dropped, unless we re-import several sources that we have always skipped.)