With VS15.8.0 I get again lots of errors from /permissive-. I was able to fix these by applying lots of this-> and redefining DECLARE_WND_SUPERCLASS from atlwin.h as used in atlctrlx.h.
Thank you for your work on /permissive- ! Some things I found: atlsplit.h breaks on DECLARE_WND_CLASS_EX() from atlwin.h. Is there a workaround? Also atlcrack.h no longer works with BEGIN_MSG_MAP() but it works with BEGIN_MSG_MAP_EX() so that's ok