It's much easier to have a single binary and multiple .mo files. It's too much maintenance work to have lots of build variations. Once the software support is implemented, anyone could contribute translations.
wxWidgets uses the gettext standard. You use the gettext tools or something like poedit to create a .po file by scanning the sourcefiles for strings and editing the translations into the .po file, then compile it into a .mo file. The program loads the .mo file at runtime and reskins all the strings. Additional languages can be added to an existing program by adding .mo files without recompiling the program.
On Windows, the .mo files would go in a lang subdirectory in the directory where the EXE is located.
Right now I'm working on JSON-RPC and command line support, but when I'm finished with that I hope to do this next.