mac: Make sandbox/ build on arm64.

Bug: 1098899
Change-Id: I7f03ab3d7305beec8057351f6c0aa50ccb9e4503
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2270700
Commit-Queue: Nico Weber <thakis@chromium.org>
Commit-Queue: Robert Sesek <rsesek@chromium.org>
Auto-Submit: Nico Weber <thakis@chromium.org>
Reviewed-by: Robert Sesek <rsesek@chromium.org>
Reviewed-by: Mark Mentovai <mark@chromium.org>
Cr-Commit-Position: refs/heads/master@{#783075}

sandbox/mac/sandbox_logging.cc

@@ -15,12 +15,20 @@
 #include <limits>
 #include <string>
 
+#if __x86_64__
 #define ABORT()                                                                \
   {                                                                            \
     asm volatile(                                                              \
         "int3; ud2; push %0;" ::"i"(static_cast<unsigned char>(__COUNTER__))); \
     __builtin_unreachable();                                                   \
   }
+#elif __arm64__
+#define ABORT()                                                             \
+  {                                                                         \
+    asm volatile("udf %0;" ::"i"(static_cast<unsigned char>(__COUNTER__))); \
+    __builtin_unreachable();                                                \
+  }
+#endif
 
 extern "C" {
 void abort_report_np(const char*, ...);