* include/winuser.h ((SPI_SETWHEELSCROLLLINES) Add define.

* include/zmouse.h (WHEEL_DELTA): Guard against prior
	definition.
	(WHEEL_PAGESCROLL): Likewise.
	(SPI_SETWHEELSCROLLLINES): Define, if not already done.

winsup/w32api/include/winuser.h

@@ -1125,6 +1125,7 @@ extern "C" {
 #define SPI_SETSOUNDSENTRY 65
 #define SPI_SETSTICKYKEYS 59
 #define SPI_SETTOGGLEKEYS 53
+#define SPI_SETWHEELSCROLLLINES 105
 #define SPI_SETWORKAREA 47
 #define SPIF_UPDATEINIFILE 1
 #define SPIF_SENDWININICHANGE 2

winsup/w32api/include/zmouse.h

@@ -21,7 +21,16 @@
 # define WM_MOUSEWHEEL (WM_MOUSELAST + 1)
 #endif
 
-#define WHEEL_DELTA 120
-#define WHEEL_PAGESCROLL UINT_MAX
+#ifndef WHEEL_DELTA
+# define WHEEL_DELTA 120
+#endif
+
+#ifndef WHEEL_PAGESCROLL
+# define WHEEL_PAGESCROLL UINT_MAX
+#endif
+
+#ifndef SPI_SETWHEELSCROLLLINES
+# define SPI_SETWHEELSCROLLLINES 105
+#endif
 
 #endif /* _ZMOUSE_H */