Fix ARM64 macro detection for Windows on ARM builds

Agent-Logs-Url: https://github.com/RenderKit/embree/sessions/71a93d2a-2cfa-4e53-ad36-40765438ddee

Co-authored-by: stefanatwork <93931354+stefanatwork@users.noreply.github.com>

Author: Copilot

common/sys/intrinsics.h

@@ -9,7 +9,7 @@
 #include <intrin.h>
 #endif
 
-#if defined(__ARM_NEON)
+#if defined(__ARM_NEON) || defined(__aarch64__)
 #include "../simd/arm/emulation.h"
 #else
 #include <immintrin.h>

common/sys/platform.h

@@ -57,6 +57,11 @@
 #define __X86_ASM__
 #endif
 
+/* normalize ARM64 platform macro */
+#if defined(_M_ARM64) || defined(_M_ARM64EC)
+#define __aarch64__
+#endif
+
 /* detect 64 bit platform */
 #if defined(__X86_64__) || defined(__aarch64__)
 #define __64BIT__