Remove SDL_config.h from the public headers

The SDL headers are no longer dependent on the build configuration.

Fixes https://github.com/libsdl-org/SDL/issues/6643 and https://github.com/libsdl-org/SDL/issues/6641

test/testautomation_sdltest.c

@@ -3,21 +3,7 @@
  */
 
 #include <limits.h>
-/* Visual Studio 2008 doesn't have stdint.h */
-#if defined(_MSC_VER) && _MSC_VER <= 1500
-#define UINT8_MAX   _UI8_MAX
-#define UINT16_MAX  _UI16_MAX
-#define UINT32_MAX  _UI32_MAX
-#define INT64_MIN    _I64_MIN
-#define INT64_MAX    _I64_MAX
-#define UINT64_MAX  _UI64_MAX
-#else
-#include <stdint.h>
-#endif
-
-#include <stdio.h>
 #include <float.h>
-#include <ctype.h>
 
 #include "SDL.h"
 #include "SDL_test.h"
@@ -1316,3 +1302,5 @@ SDLTest_TestSuiteReference sdltestTestSuite = {
     sdltestTests,
     NULL
 };
+
+/* vi: set ts=4 sw=4 expandtab: */