Update to SDL 2.24.0 and add separate macOS UB2 dylib

Update mingw and macOS SDL libraries to 2.24.0. (MSVC .lib files and
Xcode project haven't been updated.)

There is now a separate SDL dylib for macOS Universal Binary 1 and 2
because SDL 2.24.0 dropped support for macOS 10.6 (which is last to
support x86). Documentation says SDL 2.24.0 also dropped macOS 10.7
and 10.8 too. So UB2 is now 10.9 or later while 10.5 to 10.8 live in
UB1.

Compiled using osxcross with macOS 11.3 SDK. Ran "strip -x" on Windows
and macOS libraries. Ad-hoc signed dylib using PyOxidizer rcodesign to
fix digest checksums after strip.

code/SDL2/include/SDL_config_winrt.h

@@ -1,6 +1,6 @@
 /*
   Simple DirectMedia Layer
-  Copyright (C) 1997-2021 Sam Lantinga <slouken@libsdl.org>
+  Copyright (C) 1997-2022 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
@@ -92,6 +92,10 @@ typedef unsigned int uintptr_t;
 # define SIZEOF_VOIDP 4
 #endif
 
+#ifdef __clang__
+# define HAVE_GCC_ATOMICS 1
+#endif
+
 /* Useful headers */
 #define HAVE_DXGI_H 1
 #if WINAPI_FAMILY != WINAPI_FAMILY_PHONE_APP
@@ -100,6 +104,7 @@ typedef unsigned int uintptr_t;
 
 #define HAVE_MMDEVICEAPI_H 1
 #define HAVE_AUDIOCLIENT_H 1
+#define HAVE_TPCSHRD_H 1
 
 #define HAVE_LIBC 1
 #define STDC_HEADERS 1
@@ -118,6 +123,7 @@ typedef unsigned int uintptr_t;
 #define HAVE_FREE 1
 #define HAVE_ALLOCA 1
 #define HAVE_QSORT 1
+#define HAVE_BSEARCH 1
 #define HAVE_ABS 1
 #define HAVE_MEMSET 1
 #define HAVE_MEMCPY 1
@@ -190,6 +196,8 @@ typedef unsigned int uintptr_t;
 #define HAVE_TRUNCF 1
 #define HAVE__FSEEKI64 1
 
+#define HAVE_ROAPI_H  1
+
 /* Enable various audio drivers */
 #define SDL_AUDIO_DRIVER_WASAPI 1
 #define SDL_AUDIO_DRIVER_DISK   1
@@ -201,10 +209,18 @@ typedef unsigned int uintptr_t;
 #define SDL_HAPTIC_DISABLED 1
 #else
 #define SDL_JOYSTICK_VIRTUAL    1
+#if (NTDDI_VERSION >= NTDDI_WIN10)
+#define SDL_JOYSTICK_WGI    1
+#define SDL_HAPTIC_DISABLED 1
+#else
 #define SDL_JOYSTICK_XINPUT 1
 #define SDL_HAPTIC_XINPUT   1
+#endif /* WIN10 */
 #endif
 
+/* WinRT doesn't have HIDAPI available */
+#define SDL_HIDAPI_DISABLED    1
+
 /* Enable the dummy sensor driver */
 #define SDL_SENSOR_DUMMY  1
 
@@ -234,6 +250,9 @@ typedef unsigned int uintptr_t;
 /* Enable appropriate renderer(s) */
 #define SDL_VIDEO_RENDER_D3D11  1
 
+/* Disable D3D12 as it's not implemented for WinRT */
+#define SDL_VIDEO_RENDER_D3D12  0
+
 #if SDL_VIDEO_OPENGL_ES2
 #define SDL_VIDEO_RENDER_OGL_ES2 1
 #endif
@@ -241,9 +260,4 @@ typedef unsigned int uintptr_t;
 /* Enable system power support */
 #define SDL_POWER_WINRT 1
 
-/* Enable assembly routines (Win64 doesn't have inline asm) */
-#ifndef _WIN64
-#define SDL_ASSEMBLY_ROUTINES   1
-#endif
-
 #endif /* SDL_config_winrt_h_ */