Pass -DUNICODE as a CFLAG. The visual studio project asks for
a unicode (wide-string) build, but the unix makefile did not.
This fixes the build on msys2.
* [host] rename min() to LG_MIN()
* [host] format string type fixes, %Ix doesn't exist in mingw
* [host] DXGI minor fixes
* [host] mingw lacks media foundation api headers and QISearch