There are 3 choices for the alternative x86_64-linux-gnu_gl_conf (providing /etc/ld.so.conf.d/x86_64-linux-gnu_GL.conf).

  Selection    Path                                       Priority   Status
------------------------------------------------------------
* 0            /usr/lib/nvidia-378/ld.so.conf              8604      auto mode
  1            /usr/lib/nvidia-378-prime/ld.so.conf        8603      manual mode
  2            /usr/lib/nvidia-378/ld.so.conf              8604      manual mode
  3            /usr/lib/x86_64-linux-gnu/mesa/ld.so.conf   500       manual mode