Update source to SDL2 2.0.12

Edward Rudd

2020-05-02 03f8528315fa46c95991a34f3325d7b33ae5538c

 source/src/video/x11/SDL_x11vulkan.c

@@ -1,6 +1,6 @@
/*
  Simple DirectMedia Layer
  Copyright (C) 1997-2018 Sam Lantinga <slouken@libsdl.org>
  Copyright (C) 1997-2020 Sam Lantinga <slouken@libsdl.org>

  This software is provided 'as-is', without any express or implied
  warranty.  In no event will the authors be held liable for any damages
@@ -182,7 +182,7 @@
    if(videoData->vulkan_xlib_xcb_library)
    {
        PFN_vkCreateXcbSurfaceKHR vkCreateXcbSurfaceKHR =
            (PFN_vkCreateXcbSurfaceKHR)vkGetInstanceProcAddr((VkInstance)instance,
            (PFN_vkCreateXcbSurfaceKHR)vkGetInstanceProcAddr(instance,
                                                             "vkCreateXcbSurfaceKHR");
        VkXcbSurfaceCreateInfoKHR createInfo;
        VkResult result;
@@ -213,7 +213,7 @@
    else
    {
        PFN_vkCreateXlibSurfaceKHR vkCreateXlibSurfaceKHR =
            (PFN_vkCreateXlibSurfaceKHR)vkGetInstanceProcAddr((VkInstance)instance,
            (PFN_vkCreateXlibSurfaceKHR)vkGetInstanceProcAddr(instance,
                                                              "vkCreateXlibSurfaceKHR");
        VkXlibSurfaceCreateInfoKHR createInfo;
        VkResult result;