Fix darwin build

Disable host libmeminfo and showmap when building on darwin.

Test: m on darwin
Change-Id: Ie9342eff8d9e33c706edbb068d4ec405b480e599
diff --git a/libmeminfo/tools/Android.bp b/libmeminfo/tools/Android.bp
index a592a25..3968c09 100644
--- a/libmeminfo/tools/Android.bp
+++ b/libmeminfo/tools/Android.bp
@@ -67,6 +67,12 @@
         "libbase",
         "libmeminfo",
     ],
+
+    target: {
+        darwin: {
+            enabled: false,
+        },
+    },
 }
 
 cc_binary {