DMD: can't get extern __gshared to work right (vs. LDC)

[DanielG]

Follow-up:

The problem on DMD macOS is the "export" keyword. It ended up in 
my code during a similar-ish problem last year, when I was having 
trouble linking against DLL global variables on Windows.

If I remove the "export" keyword in the D interface, it will work 
on macOS but break on Windows. (To reiterate: WITHOUT "export" on 
Windows, it refuses to link. WITH "export" on Mac, it seems to 
link but with incorrect results)

Is this correct behavior?