haiku: Disable pointer history

(note from PulkoMandy on Bugzilla #4442 about why this is a desirable patch:
"The event mask: note that the window and GL view run in their own thread
which I don't expect to be too much CPU bound, and will quickly pop these
messages and forward them to the main thread in our SDL code. Therefore the
B_NO_POINTER_HISTORY should be no problem, and is the default on Haiku
anyway (it was not in BeOS, but we changed that and added a
B_FULL_POINTER_HISTORY flag to request the old behavior explicitly). So, this
seems fine.")

Partially fixes Bugzilla #4442.

src/video/haiku/SDL_BWin.h

@@ -140,6 +140,7 @@ class SDL_BWin:public BDirectWindow
             _gl_type = gl_flags;
         }
         AddChild(_SDL_GLView);
+        _SDL_GLView->SetEventMask(B_POINTER_EVENTS | B_KEYBOARD_EVENTS, B_NO_POINTER_HISTORY);
         _SDL_GLView->EnableDirectMode(true);
         _SDL_GLView->LockGL();  /* "New" GLViews are created */
         Unlock();