pacman --needed -Sy bash pacman pacman-mirrors msys2-runtime
pacman -Su
References :
http://msys2.github.io/
http://sourceforge.net/p/msys2/wiki/MSYS2%20installation/
http://stackoverflow.com/questions/30069830/how-to-install-mingw-w64-and-msys2
https://blogs.gnome.org/nacho/2014/08/01/how-to-build-your-gtk-application-on-windows/