GDB in DDT: File format not recognized

[Mike]

When I try to debug a simple hello world application, I get the
following error when running a debug build:

    Error message from debugger back end [...]hello.exe not in
executable format: File format not recognized

I'm using MinGW's GDB. The application targets 32bit and GDB is
also 32-bit:

    gdb --version
    GNU gdb (GDB) 7.6.1
    [...]
    This GDB was configured as "mingw32".

I've tried forcing both the -g and -gc options in the dub package
file but the error still exists. Did I mis-configure something?