fix linux continuous build

build/tfs/continuous-build.yml

@@ -28,7 +28,7 @@ phases:
   steps:
   - script: |
       apt-get update
-      apt-get install -y libxkbfile-dev pkg-config libsecret-1-dev libxss1 libgconf-2-4 dbus xvfb
+      apt-get install -y libxkbfile-dev pkg-config libsecret-1-dev libxss1 libgconf-2-4 dbus xvfb libgtk-3-dev
       cp build/tfs/linux/x64/xvfb.init /etc/init.d/xvfb
       chmod +x /etc/init.d/xvfb
       update-rc.d xvfb defaults