GDC generate wrong .exe ("not a valid win32 application")

[Patric Dexheimer via Digitalmars-d-learn]

Fresh install of GDC. (tried with 32x ad 32_64x)

GDC: 6.3.0
DUB: 1.3.0

dub run --build=release --arch=x86 --compiler=gdc

(...)
Running .\main
Failed to spawn new process (%1 is not a valid win32 application)