ANSI C fixes.
Removed warnings.
Made the include files self-sufficient.
Some Solaris fixes.

diff --git a/windows/scroll.c b/windows/scroll.c
index ef817a4..0bf8adf 100644
--- a/windows/scroll.c
+++ b/windows/scroll.c
@@ -9,6 +9,7 @@
 
 #include <stdlib.h>
 
+#include "wine/winuser16.h"
 #include "winuser.h"
 #include "dc.h"
 #include "win.h"