The mutex added to DirectoryParamsPanel.cpp in a recent commit breaks compilation (mutex is not part of namespace std) in all MinGW versions except the posix-seh one, due to problems with win32 threads.
Of course the toolchain can be changed, but this forces recompiling (at least) wxWidgets and boost. Also, posix-seh version only exists for 64-bit MSW, so 32-bit users are stuck.
Can std::mutex be replaced with wxMutex?
EDIT: patch added