Fix build with SVE2 (#15586)

include/SDL3/SDL_intrin.h

@@ -288,7 +288,9 @@ _m_prefetch(void *__P)
 #      define __ARM_FEATURE_SVE2 1 /* Set __ARM_FEATURE_SVE2 so that it can be used elsewhere, at compile time */
 #      define __ARM_ARCH 8
 #    endif
-#  elif !defined(SDL_PLATFORM_MACOS)  /* Apple has no AArch64 device supporting SVE2 */
+#  elif defined(SDL_PLATFORM_MACOS)
+/* Apple has no AArch64 device supporting SVE2 */
+#  elif defined(__ARM_ARCH) && (__ARM_ARCH >= 8) && (defined(__aarch64__) || defined(_M_ARM64))
 #    define SDL_SVE2_INTRINSICS 1
 #    include <arm_sve.h>
 #  endif