Prefer 32-bit host executables on Mac.

Bug: 22527295
Change-Id: I2cb1d3086b65b8227e6bdac9c0485fdc452f1e9c
diff --git a/build/Android.executable.mk b/build/Android.executable.mk
index a251c92..72cf978 100644
--- a/build/Android.executable.mk
+++ b/build/Android.executable.mk
@@ -127,6 +127,10 @@
     LOCAL_MODULE_TARGET_ARCH := $(ART_SUPPORTED_ARCH)
   endif
 
+  ifdef ART_MULTILIB_OVERRIDE_$$(art_target_or_host)
+    art_multilib := $$(ART_MULTILIB_OVERRIDE_$$(art_target_or_host))
+  endif
+
   LOCAL_MULTILIB := $$(art_multilib)
   art_out_binary_name := $$(LOCAL_MODULE)