scd-event is usable on Windows, however as far as I can tell, the file must be
a native executable (something with a MZ header). I've made a simple program
which modifies argv[0] to append ".cmd" and otherwise forward the process
creation via system(). This allows editing scd-event.cmd on the fly which is a
lot nicer, but this solution really should not be necessary. If gnupg properly
created a new process, then a user could put any executable/script at the scd-
event location and have it work (which is the expected behavior). On windows,
this may require being able to change the filename which gnupg uses for scd-
event (in order to provide a system-recognizable extension). I tried making scd-
event a symlink but this did not work either.