[WIP] Provide pip package management

[GeorgeS2019]

#9 (comment)

[GeorgeS2019]

https://github.com/touilleMan/godot-python/blob/c2f25e451a861e6ea7545fc3e96c9da99dbdb2a9/src/pythonscript.c#L337

// Entry point called by Godot
DLL_EXPORT GDExtensionBool pythonscript_init(
    const GDExtensionInterfaceGetProcAddress p_get_proc_address,
    const GDExtensionClassLibraryPtr p_library,
    GDExtensionInitialization *r_initialization
) {
    if (state != STALLED) {
        printf("Pythonscript: Invalid internal state (this should never happen !)\n");
        goto error;
    }
    state = ENTRYPOINT_CALLED;

    if (p_get_proc_address == NULL || p_library == NULL || r_initialization == NULL) {
        printf("Pythonscript: Invalid init parameters provided by Godot (this should never happen !)\n");
        goto error;
    }
    // `pythonscript_gdextension_*` must be set as early as possible given it is never
    // null-pointer checked, especially in the Cython modules
    pythonscript_gdextension_get_proc_address = p_get_proc_address;
    pythonscript_gdextension_library = p_library;

    // Check compatibility between the Godot version that has been used for building
    // (i.e. the bindings has been generated against) and the version currently executed.
    GDExtensionGodotVersion godot_version;
    {
        GDExtensionInterfaceGetGodotVersion get_godot_version = (GDExtensionInterfaceGetGodotVersion)p_get_proc_address("get_godot_version");
        get_godot_version(&godot_version);
    }
    if (godot_version.major != GODOT_VERSION_MAJOR || godot_version.minor < GODOT_VERSION_MINOR) {
        char buff[256];
        snprintf(
            buff,
            sizeof(buff),
            "Pythonscript: Incompatible Godot version (expected ~%d.%d, got %s)\n",
            GODOT_VERSION_MAJOR,
            GODOT_VERSION_MINOR,
            godot_version.string
        );
        GD_PRINT_ERROR(buff);
        goto error;
    }

    // Initialize as early as possible, this way we can have 3rd party plugins written
    // in Python/Cython that can do things at this level
    r_initialization->minimum_initialization_level  = GDEXTENSION_INITIALIZATION_CORE;
	r_initialization->userdata = NULL;
    r_initialization->initialize = _initialize;
    r_initialization->deinitialize = _deinitialize;

    state = ENTRYPOINT_RETURNED;
    return true;

error:
    state = CRASHED;
    return false;
}

[GeorgeS2019]

PYTHONHOME versus GODOT_PYTHON_MODULE_LIB_DIR

 // Set PYTHONHOME  => is better than non standard environmental variable GODOT_PYTHON_MODULE_LIB_DIR

https://github.com/touilleMan/godot-python/blob/c2f25e451a861e6ea7545fc3e96c9da99dbdb2a9/src/pythonscript.c#L124