Compile fix for MSVC: Include <io.h>

This include is needed for _commit(..) which is used in mingw.h.

Signed-off-by: Vincent van Ravesteijn <vfr@lyx.org>
Acked-by: Erik Faye-Lund <kusmabite@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

compat/msvc.h

@@ -4,6 +4,7 @@
 #include <direct.h>
 #include <process.h>
 #include <malloc.h>
+#include <io.h>
 
 /* porting function */
 #define inline __inline