Ref issue #54.
* Fixed icon filename capitalization * Created mingw cmake toolchain * Adjusted CMakeLists.txt for compatibility * Small mingwcc.cmake cleanup * Added cross-compilation instructions to readme * Update README.md Fixed typo Co-authored-by: Nicola Orlando <nicolaorlando24@gmail.com> Co-authored-by: Muzychenko Andrey <33288308+k4zmu2a@users.noreply.github.com>