Make it possible to cross-compile for Windows

Currently only building with MSVC is supported, but for usage in VLC we need to be able to cross-compile with mingw for Windows.

This requires the build system to be rewritten, as currently (as far as I understood) only linux is in the autotools files. And then it needs to be checked what needs to be adapted for it to compiler with mingw.

• Add Windows to build system
• Check what changes are required for mingw
• Implement a dialog to ask the user if they want to send the report