Android export does not include native libraries when using Custom Template

[madmiraal]

Godot version

3.3.2.stable

System information

Ubuntu 21.04

Issue description

Everything works fine when exporting to Android using the default template. However, when exporting to Android using the custom template, the project's native libraries are missing, and the following logcat errors are produced:

2021-06-23 17:35:37.925 5900-5957/org.godotengine.simple E/godot: **ERROR**: Can't open dynamic library: libsimple.android.x86.so, error: dlopen failed: library "libsimple.android.x86.so" not found.
2021-06-23 17:35:37.925 5900-5957/org.godotengine.simple E/godot:    At: platform/android/os_android.cpp:228:open_dynamic_library() - Condition "!p_library_handle" is true. Returned: ERR_CANT_OPEN
2021-06-23 17:35:37.925 5900-5957/org.godotengine.simple E/godot: **ERROR**: No valid library handle, can't get symbol from GDNative object
2021-06-23 17:35:37.925 5900-5957/org.godotengine.simple E/godot:    At: modules/gdnative/gdnative.cpp:502:get_symbol() - No valid library handle, can't get symbol from GDNative object
2021-06-23 17:35:37.925 5900-5957/org.godotengine.simple E/godot: **ERROR**: No nativescript_init in "res://lib/libsimple.android.x86.so" found
2021-06-23 17:35:37.925 5900-5957/org.godotengine.simple E/godot:    At: modules/gdnative/nativescript/nativescript.cpp:1482:init_library() - No nativescript_init in "res://lib/libsimple.android.x86.so" found
2021-06-23 17:35:37.927 5900-5957/org.godotengine.simple E/godot: **SCRIPT ERROR**: Attempt to call function 'new' in base 'NativeScript' on a null instance.
2021-06-23 17:35:37.927 5900-5957/org.godotengine.simple E/godot:    At: res://Main.gdc:5:_ready() - Attempt to call function 'new' in base 'NativeScript' on a null instance.

Steps to reproduce

Add a native library to your project load and access it within your project. Export to Android, install it on a device or emulator and confirm that everything works.

Install the Android Build Template, check "Use Custom Build". Export to Android, install it on a device or emulator and confirm that the library is not there.

Minimal reproduction project

simple.zip

[m4gr3d]

@madmiraal I'm not sure I understand the issue. Can you describe what you're trying to do, and the process (the more details the better!) through which you are able to accomplish that with the default template.