[GDExtension] Use function names with underscore for TextServer extension, add macros to generate wrappers for module functions.

[bruvzg]

• Change TextServerExtension virtual method names to start with underscore.
• Add MODBIND* macros to automatically generate wrappers and method definitions to use same code as built-in module or GDExtension.
• Re-enable test to check if virtual method names start with underscore.
• Update TextServer code to build as GDExtension after FileAccess and some other recent changes.

Fixes #64814

Depends on godotengine/godot-cpp#870 (only for TextServer GDEXtension builds, it won't break CI or other GDExtension modules).

[MGilleronFJ]

It looks like this is for TextServer, but I had the same problem where my project can build both as a module and as GDExtension.
See for example what I had to do:
https://github.com/Zylann/godot_voxel/blob/dc9f1a7de0c3003f8a2adf5ecd5d231418db0ccf/editor/terrain/voxel_terrain_editor_plugin.h#L19
I have no idea how this MODBIND* works, but would it help with my use case?
(as you might notice, sometimes differences are more than just the _. See also a much worse situation in https://github.com/Zylann/godot_voxel/blob/dc9f1a7de0c3003f8a2adf5ecd5d231418db0ccf/util/godot/editor_import_plugin.h#L80)

[bruvzg]

I have no idea how this MODBIND* works, but would it help with my use case?
as you might notice, sometimes differences are more than just the _. See also a much worse situation in

The only thing it's doing is generating funcname -> _funcname wrapper and define for _funcname (with or without override).

As for the other differences in the https://github.com/Zylann/godot_voxel/blob/dc9f1a7de0c3003f8a2adf5ecd5d231418db0ccf/util/godot/editor_import_plugin.h#L80

HashMap and List can be used in the GDExtension. Some like Node * ↔ Object * are clearly bugs and should be fixed (but not directly related to this PR). For the other API differences, ifdefs are probably the only way to do it (the only other option is to change C++ API for specific cases in the engine, which was done for the TextServer some time ago).

[akien-mga]

Thanks!