zlib: build src/test/example.c

Despite the misleading name, it's as close to a unit test that
we'll get.

Test: make
Change-Id: Ic10ade9c5d0295041b26ff878f2476c900196a88
diff --git a/Android.bp b/Android.bp
index 52c3e3c..9d1dde1 100644
--- a/Android.bp
+++ b/Android.bp
@@ -83,6 +83,20 @@
     stl: "none",
 }
 
+cc_binary {
+    name: "zlib_example",
+    srcs: ["src/test/minigzip.c"],
+    shared_libs: ["libz"],
+    stl: "none",
+}
+
+cc_binary_host {
+    name: "zlib_example_host",
+    srcs: ["src/test/example.c"],
+    static_libs: ["libz"],
+    stl: "none",
+}
+
 // This module is defined in development/ndk/Android.bp. Updating these headers
 // to be usable for any API level is going to be some work (at the very least,
 // there's a ZLIB_VERNUM that will need to be handled since early versions of