[AD] show_os_cursor fix

[Elias Pschernig <elias@xxxxxxxxxx>]

Apparently, there was a race condition in show_os_cursor, which would
somehow sometimes trigger the software cursor to try drawing itself and
crash the program.

The attached patch fixes it, I simply copied the remove_int/install_int
guard from show_mouse.

-- 
Elias Pschernig

Index: src/mouse.c
===================================================================
--- src/mouse.c	(revision 5659)
+++ src/mouse.c	(working copy)
@@ -529,9 +529,12 @@
  */
 int show_os_cursor(int cursor)
 {
+   int r = -1;
    if (!mouse_driver)
-      return -1;
+      return r;
 
+   remove_int(mouse_move);
+
    gfx_capabilities &= ~(GFX_HW_CURSOR|GFX_SYSTEM_CURSOR);
    if (cursor != MOUSE_CURSOR_NONE) {
 
@@ -544,24 +547,26 @@
          if (mouse_driver->select_system_cursor) {
             if (mouse_driver->select_system_cursor(cursor) != 0) {
                gfx_capabilities |= (GFX_HW_CURSOR|GFX_SYSTEM_CURSOR);
-               return 0;
+               r = 0;
+               goto done;
             }
          }
-         return -1;
+         goto done;
       }
       else {
          /* set custom hardware cursor */
          if (gfx_driver) {
             if (gfx_driver->set_mouse_sprite) {
                if (gfx_driver->set_mouse_sprite(mouse_sprite, mouse_x_focus, mouse_y_focus))
-                  return -1;
+                  goto done;
             }
             if (gfx_driver->show_mouse) {
                if (gfx_driver->show_mouse(screen, mouse_x, mouse_y))
-                  return -1;
+                  goto done;
             }
             gfx_capabilities |= GFX_HW_CURSOR;
-            return 0;
+            r = 0;
+            goto done;
          }
       }
    }
@@ -570,7 +575,10 @@
          gfx_driver->hide_mouse();
    }
 
-   return -1;
+done:
+   if (mouse_driver->timer_poll) 
+      install_int(mouse_move, 10);
+   return r;
 }