It is a remnant of the Active days and didn't even compile.
This patch only removes those ifdefs, it doesn't fix any issues I found during (e.g. double lookups or the fact that KRun::autoDelete is the default now)

I think the entire KDE_PLATFORM_FEATURE_BINARY_COMPATIBLE_FEATURE_REDUCTION could be removed, but one step at a time

Compiles, dropping files on desktop still asks what do to and adding a widget or setting as wallpaper works