I tested this last patch on Cygwin and it does not work well. Specifically I have to delete <userdir>/lyxrc.defaults otherwise I only get "PDF (dvipdfm)" and "PDF (pdflatex)" in the View menu.
That is the design. Use the old lyxrc.default, '' will be there for not-found viewers and lyx will not do anything. After reconfigure, the "" will be replaced by "auto", and this is when autoViewable starts to work.
Deleting <userdir>/lyxrc.defaults it works. But this file is restored whenever reconfiguring.
This is weird to me. Any idea? Do you see "auto" in lyxrc.default after reconfiguration? Bo