VS2010 buildfixes.

The main issue was mostly that we have to build C files as C++ in some
cases, and extern "C" wasn't being used everywhere, so linker errors
popped up. The rest is the usual tedious VS2010 stuff like casting void*
to other stuff, so this commit as a whole is pretty boring!

desktop_version/src/Xoshiro.c

@@ -1,4 +1,4 @@
-#include <stdint.h>
+#include "Xoshiro.h"
 
 #include "Vlogging.h"