Linux RobsCNC 5.10.0-8-rt-amd64 #1 SMP PREEMPT_RT Debian 5.10.46-4 (2021-08-03) x86_64 GNU/Linux

$ ./linuxcnc
LINUXCNC - 2.9.0~pre0
Machine configuration directory is '/home/rob/linuxcnc-dev/configs/sim/gmoccapy'
Machine configuration file is '4_axis.ini'

check_config: (trivkins kinematics) WARNING:
  Unexpected multiple values [JOINT_0]HOME: 0.000 10
  Unexpected multiple values [JOINT_1]HOME: 0.000 10
  Unexpected multiple values [JOINT_2]HOME: 0.0 -10

Starting LinuxCNC...
Found file(REL): ./core_sim4.hal
Note: Using POSIX realtime

identityKinematicsSetup: coordinates:xyzc
   Joint 0 ==> Axis X
   Joint 1 ==> Axis Y
   Joint 2 ==> Axis Z
   Joint 3 ==> Axis C
identityKinematicsSetup: Recommend: kinstype=both

Found file(REL): ./spindle_sim.hal
Found file(REL): ./simulated_home.hal
link (updating variable file): No such file or directory
Traceback (most recent call last):
  File "/home/rob/linuxcnc-dev/bin/gmoccapy", line 43, in <module>
    import gladevcp.makepins   # needed for the dialog"s calculator widget
  File "/home/rob/linuxcnc-dev/lib/python/gladevcp/__init__.py", line 1, in <module>
    from .hal_pythonplugin import *
  File "/home/rob/linuxcnc-dev/lib/python/gladevcp/hal_pythonplugin.py", line 30, in <module>
    from .hal_gremlin import HAL_Gremlin
  File "/home/rob/linuxcnc-dev/lib/python/gladevcp/hal_gremlin.py", line 36, in <module>
    import gremlin
  File "/home/rob/linuxcnc-dev/lib/python/gremlin.py", line 47, in <module>
    from OpenGL.GL import *
ModuleNotFoundError: No module named 'OpenGL'
Shutting down and cleaning up LinuxCNC...
task: 1502 cycles, min=0.000012, max=0.001587, avg=0.001056, 0 latency excursions (> 10x expected cycle time of 0.001000s)
Note: Using POSIX realtime
LinuxCNC terminated with an error.  You can find more information in the log:
    /home/rob/linuxcnc_debug.txt
and
    /home/rob/linuxcnc_print.txt
as well as in the output of the shell command 'dmesg' and in the terminal