writers test: use writeC with library for testing

pkgs/build-support/writers/test.nix

@@ -1,4 +1,16 @@
-{ stdenv, lib, runCommand, haskellPackages, nodePackages, perlPackages, python2Packages, python3Packages, writers, writeText }:
+{
+  glib,
+  haskellPackages,
+  lib,
+  nodePackages,
+  perlPackages,
+  python2Packages,
+  python3Packages,
+  runCommand,
+  stdenv,
+  writers,
+  writeText
+}:
 with writers;
 let
 
@@ -72,9 +84,19 @@ let
      if [[ "test" == "test" ]]; then echo "success"; fi
     '';
 
-    c = writeC "test_c" { libraries = [ ]; } ''
+    c = writeC "test_c" { libraries = [ glib.dev ]; } ''
+      #include <gio/gio.h>
       #include <stdio.h>
       int main() {
+        GApplication *application = g_application_new ("hello.world", G_APPLICATION_FLAGS_NONE);
+        g_application_register (application, NULL, NULL);
+        GNotification *notification = g_notification_new ("Hello world!");
+        g_notification_set_body (notification, "This is an example notification.");
+        GIcon *icon = g_themed_icon_new ("dialog-information");
+        g_notification_set_icon (notification, icon);
+        g_object_unref (icon);
+        g_object_unref (notification);
+        g_object_unref (application);
         printf("success\n");
         return 0;
       }