Fix mac build

Change-Id: I18bf6c9feadb224579283418c6ddb35e41a431c3
diff --git a/BUILD.gn b/BUILD.gn
index 13a90b2..2af4f42 100644
--- a/BUILD.gn
+++ b/BUILD.gn
@@ -68,12 +68,14 @@
     ]
   }
 
-  # Used by Android's statsd in /frameworks/base/cmds.
-  static_library("perfetto_protos_lite") {
-    deps = [
-      "gn:default_deps",
-      "protos:lite",
-    ]
+  if (build_with_android) {
+    # Used by Android's statsd in /frameworks/base/cmds.
+    static_library("perfetto_protos_lite") {
+      deps = [
+        "gn:default_deps",
+        "protos:lite",
+      ]
+    }
   }
 
   if (monolithic_binaries) {