Fix mac build by disabling art-module-host-exports

Test: m nothing on mac
Bug: 142935992
Change-Id: I8a58c84176c0520910c03b002f812aabb0056810
diff --git a/build/sdk/Android.bp b/build/sdk/Android.bp
index a2d802f..9a866b9 100644
--- a/build/sdk/Android.bp
+++ b/build/sdk/Android.bp
@@ -38,6 +38,9 @@
             // implementation and cannot be overridden any other way.
             compile_multilib: "64",
         },
+        darwin: {
+            enabled: false,
+        },
     },
     java_libs: [
         "timezone-host",