[ASan] Implement asan_mz_size(), asan_mz_force_lock() and asan_mz_force_unlock() for allocator2.
Switch to allocator2 on Darwin.

llvm-svn: 174603
diff --git a/compiler-rt/lib/asan/asan_allocator.h b/compiler-rt/lib/asan/asan_allocator.h
index d8cef68..724dbe8 100644
--- a/compiler-rt/lib/asan/asan_allocator.h
+++ b/compiler-rt/lib/asan/asan_allocator.h
@@ -24,7 +24,7 @@
 // will co-exist in the source base for a while. The actual allocator is chosen
 // at build time by redefining this macro.
 #ifndef ASAN_ALLOCATOR_VERSION
-# if ASAN_LINUX && !ASAN_ANDROID
+# if (ASAN_LINUX && !ASAN_ANDROID) || ASAN_MAC
 #  define ASAN_ALLOCATOR_VERSION 2
 # else
 #  define ASAN_ALLOCATOR_VERSION 1