`build_config_windows`: define `HAVE_STDARG/STDDEF_H` outside of

condition.
They are defined in both `#if HAVE_LIBC` and its `#else` anyway.
[sdl-ci-filter msvc-*]

(cherry picked from commit ea995b1694e2af30a9dea1a1dadaa0658540d848)

include/build_config/SDL_build_config_windows.h

@@ -111,6 +111,9 @@ typedef unsigned int uintptr_t;
 # define SDL_DISABLE_AVX 1
 #endif
 
+#define HAVE_STDARG_H 1
+#define HAVE_STDDEF_H 1
+
 /* This can be disabled to avoid C runtime dependencies and manifest requirements */
 #ifndef HAVE_LIBC
 #define HAVE_LIBC 1
@@ -122,8 +125,6 @@ typedef unsigned int uintptr_t;
 #define HAVE_LIMITS_H 1
 #define HAVE_MATH_H 1
 #define HAVE_SIGNAL_H 1
-#define HAVE_STDARG_H 1
-#define HAVE_STDDEF_H 1
 #define HAVE_STDIO_H 1
 #define HAVE_STDLIB_H 1
 #define HAVE_STRING_H 1
@@ -210,10 +211,7 @@ typedef unsigned int uintptr_t;
 #if _MSC_VER >= 1400
 #define HAVE__FSEEKI64 1
 #endif
-#endif    /* _MSC_VER */
-#else
-#define HAVE_STDARG_H 1
-#define HAVE_STDDEF_H 1
+#endif /* _MSC_VER */
 #endif
 
 /* Enable various audio drivers */