SDL: Fix the erroneous generation of mouse-down events from touch-move events.

From 53df0e6619f16bbee45b4c764b3772e077879ced Mon Sep 17 00:00:00 2001
From: ulatekh <[EMAIL REDACTED]>
Date: Fri, 21 Jan 2022 17:15:18 -0700
Subject: [PATCH] Fix the erroneous generation of mouse-down events from
 touch-move events.

The issue is that MS Windows synthesizes a mouse-move event in response
to touch-move events, and those mouse-move events are NOT labeled as
coming from a touch (e.g. GetMouseMessageSource() will not return
SDL_MOUSE_EVENT_SOURCE_TOUCH for those synthesized mouse-move events).

In addition, there seems to be no way to prevent this from happening;
https://gist.github.com/vbfox/1339671 claims to demonstrate a technique
to prevent it, but in my experience, it doesn't work.

Because of this, the "fallthrough" case can't test that the synthesized
mouse-move came from a touch-move, and starts erroneously pressing down
the mouse-button, leading to massive confusion in the client
application.
---
 src/video/windows/SDL_windowsevents.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/src/video/windows/SDL_windowsevents.c b/src/video/windows/SDL_windowsevents.c
index 471bbee8671..34cbcac7b6e 100644
--- a/src/video/windows/SDL_windowsevents.c
+++ b/src/video/windows/SDL_windowsevents.c
@@ -732,8 +732,8 @@ WIN_WindowProc(HWND hwnd, UINT msg, WPARAM wParam, LPARAM lParam)
                 }
             }
         }
-        /* don't break here, fall through to check the wParam like the button presses */
-        SDL_FALLTHROUGH;
+        break;
+
     case WM_LBUTTONUP:
     case WM_RBUTTONUP:
     case WM_MBUTTONUP: