First of all you need to replace the gold linker with bfd in the gst-android-1.14/armv7/share/gst-android/ndk-build/gstreamer-1.0.mk
See also this NDK issue
Then to build and deploy the player app to your device, use a command similar to:
$ GSTREAMER_ROOT_ANDROID=/path/to/gst-android-1.14/ PATH=~/dev/android/tools/bin:~/dev/android/ndk-bundle:$PATH ANDROID_HOME="$HOME/dev/android/" ./gradlew installDebug$ adb shell am start -n org.freedesktop.gstreamer.play/.Play http:https://ftp.nluug.nl/pub/graphics/blender/demo/movies/Sintel.2010.720p.mkvTo see the GStreamer logs at runtime:
$ adb logcat | egrep '(gst)'