Merge commit 'c7f8138e3f98f195af6c8735b9bc41e72154ae9f' into HEAD

Change-Id: If803204ab7eed86a2d11b04ecc5af235a8ab6b9a
diff --git a/Android.bp b/Android.bp
index a8538b2..2909031 100644
--- a/Android.bp
+++ b/Android.bp
@@ -19,6 +19,7 @@
     name: "libgsl",
     host_supported: true,
     export_include_dirs: ["include"],
+    cflags: ["-Wall", "-Werror"],
 }
 
 // Tests pending approval of external/Microsoft-unittest-cpp: http://b/32512867