I want to revisit this issue.
Building 64 bit on Linux, release or debug, is fast. However, building 64 bit release on Windows 10 is super slow. I have a cross platform app that uses gtk-d. Today, I updated DMD to 2.079.1 and the gtk-d lib to 3.8.0. When I performed a debug build on Windows 10, it only took a few seconds to build gtk-d. I attempted to build release but canceled the build after a couple of hours. I tried building 32 bit release on Windows and while it took a lot longer than debug, it still completed in a reasonable amount of time (it wouldn't link, though, probably because I'm missing some 32 libraries).
Does anyone have any idea why 64 bit release builds on Windows would take so long?