Unable to build for/with MinGW 64bit on Windows10

Hello,

i have problems to build the sdk using both cmake commandline and gui for MinGW 64bit on Windows 10.
I followed the build instructions on the git side.
I got:
CMake Error at vstgui4/vstgui/standalone/cmake/modules/vstgui_add_executable.cmake:45 (target_link_libraries):
Cannot specify link libraries for target “ImageStitcher” which is not built
by this project.

Then i disabled in cmake gui SMTG_ADD_VSTGUI. This results in a Makefile. Now a call to mingw32-make brings the following to me:
g++.exe: error: /MP: No such file or directory
g++.exe: error: /ZI: No such file or directory
g++.exe: error: /MDd: No such file or directory
g++.exe: error: /fp:fast: No such file or directory

After short googleing i found out, that MinGW doesn’t know the switches /MP /ZI MDd /fp:fast. So i began to remove them. The build runs modul by modul after removing the unknown switches.
Then the build crashes, here the first of a lot of lines:
fdynlib.cpp: In member function ‘bool Steinberg::FDynLibrary::init(const tchar*, bool)’:
…\VST_SDK\VST3_SDK\base\source\fdynlib.cpp:108:28: error: no matching function for call to ‘append(const wchar_t [5])’
name.append (STR (“.dll”));

At these point i gave up.

How can i build the sdk using MinGW 64bit on Windows10?
My goal is to develop applications using Qt5 (Qt Creator) with MinGW toolchain.

Greetings,
Hardy