Use __aarch64__ instead of __arm64__ to detect AArch64

The latter name was used by Apple in their internal AArch64 LLVM backend,
but has since been merged into LLVM upstream and renamed to AArch64.

https://github.com/llvm-mirror/llvm/commit/29f94c72014eaa5d0d3b920686e68



Change-Id: I319f42f07c95dfbcd121134fbe6e554e2d36453d
Reviewed-by: Thiago Macieira <thiago.macieira@intel.com>

src/corelib/global/qprocessordetection.h

@@ -87,9 +87,9 @@
     ARM is bi-endian, detect using __ARMEL__ or __ARMEB__, falling back to
     auto-detection implemented below.
 */
-#if defined(__arm__) || defined(__TARGET_ARCH_ARM) || defined(_M_ARM) || defined(__arm64__)
+#if defined(__arm__) || defined(__TARGET_ARCH_ARM) || defined(_M_ARM) || defined(__aarch64__)
 #  define Q_PROCESSOR_ARM
-#  if defined(__arm64__)
+#  if defined(__aarch64__)
 #    define Q_PROCESSOR_ARM_64
 #  else
 #    define Q_PROCESSOR_ARM_32