Mujoco, dm_control, EGL Errors

Hello, whatever the version of dm_control I set I keep getting this errors.

``` env: MUJOCO_GL=egl
---------------------------------------------------------------------------
AttributeError Traceback (most recent call last)
Cell In[9], line 4
1 get_ipython().run_line_magic('env', 'MUJOCO_GL=egl')
2 from typing import Sequence, Tuple
----> 4 from dm_control import suite
5 from dm_control.rl import control
6 from IPython.display import HTML

File ~/.local/lib/python3.8/site-packages/dm_control/suite/__init__.py:24
20 import itertools
22 from dm_control.rl import control
---> 24 from dm_control.suite import acrobot
25 from dm_control.suite import ball_in_cup
26 from dm_control.suite import cartpole

File ~/.local/lib/python3.8/site-packages/dm_control/suite/acrobot.py:20
16 """Acrobot domain."""
18 import collections
---> 20 from dm_control import mujoco
21 from dm_control.rl import control
22 from dm_control.suite import base

File ~/.local/lib/python3.8/site-packages/dm_control/mujoco/__init__.py:18
1 # Copyright 2017 The dm_control Authors.
...
---> 87 raw_eglQueryString = _p.PLATFORM.EGL.eglQueryString
88 raw_eglQueryString.restype = ctypes.c_char_p
89 raw_eglQueryString.__doc__ = """Raw version of eglQueryString that does not check for availability"""

AttributeError: 'NoneType' object has no attribute 'eglQueryString'
```

I am desperate to know if someone has found a fix.

首先，使用 Python 3.8 和 MUJOCO_GL=egl 重现从 dm_control.suite 的导入，然后检查 dm_control/mujoco/__init__.py 中 eglQueryString 访问附近的代码。确定该失败是环境问题还是包问题；当原因以及经过验证的修复或设置要求都已记录，并且导入成功时，即表示完成。

由索引模型根据 Issue 内容生成。