Enable libarect for Windows

This is needed to use skia in Android Studio for Windows.

Bug: 117921091
Test: sdk build
Change-Id: I84cc869e9ff65819c781fbab2e5c000432a2259a
diff --git a/libs/arect/Android.bp b/libs/arect/Android.bp
index a20154f..ad8287c 100644
--- a/libs/arect/Android.bp
+++ b/libs/arect/Android.bp
@@ -25,4 +25,9 @@
     host_supported: true,
     vendor_available: true,
     export_include_dirs: ["include"],
+    target: {
+        windows: {
+            enabled: true,
+        },
+    },
 }