Remove redundant $@ in mingw_cmake and mingw_meson.
    
    $@ is not used by the RPM macro _in RPM_ since it is executed as a line
    by itself, not a script or function.
    
    There's already a $@ in the mingw-scripts.sh file, so when expanded from
    the macro, the script contains two $@, sending redundant arguments to
    cmake and meson.