[ASan]: re-enable noreturn attribute on posix

git-svn-id: https://llvm.org/svn/llvm-project/compiler-rt/trunk@153082 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/asan/asan_rtl.cc b/lib/asan/asan_rtl.cc
index 0c085f6..20cfddb 100644
--- a/lib/asan/asan_rtl.cc
+++ b/lib/asan/asan_rtl.cc
@@ -106,7 +106,10 @@
 
 void AsanDie() {
   static int num_calls = 0;
-  if (AtomicInc(&num_calls) > 1) return;  // Don't die twice.
+  if (AtomicInc(&num_calls) > 1) {
+    // Don't die twice - run a busy loop.
+    while (1) { }
+  }
   if (FLAG_sleep_before_dying) {
     Report("Sleeping for %d second(s)\n", FLAG_sleep_before_dying);
     SleepForSeconds(FLAG_sleep_before_dying);