How to fix "Error symbol '.....' is already defined"

[Vincent R via Digitalmars-d-learn]

Hi,

I have a small project and I would like to use D to build it.
I am working on Windows and I have already generated a gdc 
compiler through msys2/mingw64 and now I would like to compile 
the old.unmaintained wxWidgets wrapper called wxd.
I have forked the project here: https://github.com/vrichomme/wxd 
and tried to fix the easiest errors but now there is still an 
error about symbol already defined:

http://dpaste.dzfl.pl/c925e7f888e8

By looking at 
https://github.com/vrichomme/wxd/blob/master/src/wx/TreeCtrl.d do 
you know why I get this error ?
When using dmd I still have the warning but the linker ignores 
it, however since my project is for a raspberrypi I prefer to use 
the same toolchain on destop(gdc).

Thanks