Tools like designer, assistant and probalbly others built by configure && make are built in debug and release mode, while this is odd behavior at best. These tools are final. If someone needs to track bug, they will surely be able to compile a debug version themselves if needed. This increases compile time and is unnecessary. It probably interferes with the copy operation too:

debug build assistant.exe => copy "assistant.exe" (debug version does not have d-suffix!) to /bin
release build assistant.exe => copy "assistant.exe" (release) => error, file already exists, 0 files copied... and you end up with a debug version?