Removed a lot of occurences of windows.h (and added necessary other
includes).

diff --git a/memory/selector.c b/memory/selector.c
index 6480aec..d3bbdbb 100644
--- a/memory/selector.c
+++ b/memory/selector.c
@@ -5,7 +5,7 @@
  */
 
 #include <string.h>
-#include "windows.h"
+#include "wine/winbase16.h"
 #include "ldt.h"
 #include "miscemu.h"
 #include "selectors.h"