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_math.c

@@ -3349,4 +3349,11 @@ static const SDLTest_TestCaseReference *mathTests[] = {
     NULL
 };
 
-SDLTest_TestSuiteReference mathTestSuite = { "Math", NULL, mathTests, NULL };
+SDLTest_TestSuiteReference mathTestSuite = {
+    "Math",
+    NULL,
+    mathTests,
+    NULL
+};
+
+/* vi: set ts=4 sw=4 expandtab: */