/CtrlLib/MSYS_MinGW_w64_x86_64.Debug.Debug_Full.Gui.Mt.Share d\$blitz.o:$blitz.cpp:(.data+0xe30): more undefined references to `__gxx_personality_seh0'
Nevermind, it was a compiler mismatch error. I used an MinGW-w64 builded with SEH exception mechanism, but the official Gstreamer Windows build uses SJLJ exception mechanism.
Using a SJLJ version of MinGW-w64 removes de error.