Ok, I ran it again with the verbose option and here is the output:
ERROR: get_language_code: Invalid locale 'C'.
At: core/translation.cpp:958.
ERROR: set_locale: Unsupported locale 'C', falling back to 'en'.
At: core/translation.cpp:982.
Godot Engine v3.3.2.stable.custom_build.7610409b8 - https://godotengine.org
Unsupported locale 'C', falling back to 'C'.
Loading resource: res://localization/cd_strings.en.translation
Loading resource: res://fonts/DefaultFont.tres
Loading resource: res://default_theme.theme
Loading resource: res://styles/button/button_disabled.stylebox
Loading resource: res://textures/UI/buttons/button_white.atlastex
Loading resource: res://textures/UI/UI.png
...
Construct gdnative interface
Destruct gdnative interface
Class 'AudioEffectLimiterInstance' is not exposed, skipping.
Class 'BulletPhysicsDirectBodyState' is not exposed, skipping.
Class 'BulletPhysicsDirectSpaceState' is not exposed, skipping.
Class 'BulletPhysicsServer' is not exposed, skipping.
Class 'DynamicFontAtSize' is not exposed, skipping.
Class 'GDScriptNativeClass' is not exposed, skipping.
Class 'IP_Unix' is not exposed, skipping.
Class 'InputDefault' is not exposed, skipping.
Class 'Physics2DDirectBodyStateSW' is not exposed, skipping.
Class 'Physics2DDirectSpaceStateSW' is not exposed, skipping.
Class 'Physics2DServerSW' is not exposed, skipping.
Class 'ResourceImporterMP3' is not exposed, skipping.
Class 'ResourceImporterOGGVorbis' is not exposed, skipping.
Loading resource: /home/vagrant/build/com.atr.carpediem/fake_user_home/.config/godot/editor_settings-3.tres
EditorSettings: Load OK!
...
Loading resource: res://textures/UI/tile icons/tile_icon_mpa.atlastex
I cut out a bunch of the "Loading resource" lines. After that last line it just sits there doing nothing for an hour or so then the runner times out.
On my tablet computer it only takes a minute or two to export the apk.