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

diff --git a/loader/resource.c b/loader/resource.c
index 082bbff..d14f0c1 100644
--- a/loader/resource.c
+++ b/loader/resource.c
@@ -12,7 +12,10 @@
 #include <sys/stat.h>
 #include <fcntl.h>
 #include <unistd.h>
-#include "windows.h"
+#include "ntdll.h"
+#include "winbase.h"
+#include "winuser.h"
+#include "wine/winbase16.h"
 #include "wine/winuser16.h"
 #include "gdi.h"
 #include "global.h"