I have some good news! It works (Simplest test case). I spent several hours trying to track down where my code translation could be causing problems. And have concluded that core.sys.posix.sys.stat.stat_t is not correct for my 32bit Debian Linux machine.
I realize this is a big claim, so I'm going to look into it some more. But to get my code working I moved the getattr function into a C file and called that instead of using it from D. I also noticed that the value set to stat_t.st_mode would not be returned when requesting it back. Thank you Simen and div0. 1. https://github.com/he-the-great/Fused
