Update SDL to Hg d7abc11bb69a

https://github.com/cgutman/moonlight-deps/commit/20ce1c15eddb0ee9b216b0928844412e3e63e1d6

libs/windows/include/SDL_config_windows.h

@@ -1,6 +1,6 @@
 /*
   Simple DirectMedia Layer
-  Copyright (C) 1997-2020 Sam Lantinga <slouken@libsdl.org>
+  Copyright (C) 1997-2021 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
@@ -119,9 +119,6 @@ typedef unsigned int uintptr_t;
 #define HAVE_STRRCHR 1
 #define HAVE_STRSTR 1
 /* #undef HAVE_STRTOK_R */
-#if defined(_MSC_VER)
-#define HAVE_STRTOK_S 1
-#endif
 /* These functions have security warnings, so we won't use them */
 /* #undef HAVE__LTOA */
 /* #undef HAVE__ULTOA */
@@ -172,7 +169,12 @@ typedef unsigned int uintptr_t;
 /* These functions were added with the VC++ 2013 C runtime library */
 #if _MSC_VER >= 1800
 #define HAVE_STRTOLL 1
+#define HAVE_STRTOULL 1
 #define HAVE_VSSCANF 1
+#define HAVE_LROUND 1
+#define HAVE_LROUNDF 1
+#define HAVE_ROUND 1
+#define HAVE_ROUNDF 1
 #define HAVE_SCALBN 1
 #define HAVE_SCALBNF 1
 #define HAVE_TRUNC  1
@@ -215,7 +217,13 @@ typedef unsigned int uintptr_t;
 /* Enable various input drivers */
 #define SDL_JOYSTICK_DINPUT 1
 #define SDL_JOYSTICK_HIDAPI 1
+#ifndef __WINRT__
+#define SDL_JOYSTICK_RAWINPUT   1
+#endif
 #define SDL_JOYSTICK_VIRTUAL    1
+#ifdef SDL_WINDOWS10_SDK
+#define SDL_JOYSTICK_WGI    1
+#endif
 #define SDL_JOYSTICK_XINPUT 1
 #define SDL_HAPTIC_DINPUT   1
 #define SDL_HAPTIC_XINPUT   1
@@ -227,6 +235,7 @@ typedef unsigned int uintptr_t;
 #define SDL_LOADSO_WINDOWS  1
 
 /* Enable various threading systems */
+#define SDL_THREAD_GENERIC_COND_SUFFIX 1
 #define SDL_THREAD_WINDOWS  1
 
 /* Enable various timer systems */