ovos-buildroot: glxtokens.h error when running 'make rpi3_64-gui'

I am building for the RPi3 on Ubuntu 20.04 and wanted to share an error I got in case it is helpful for you all developing this great software. It seems the program cannot find the glxtokens.h file or directory. Any suggestions?

In file included from ../../3rdparty/chromium/gpu/command_buffer/service/gl_utils.h:20,
                 from ../../3rdparty/chromium/gpu/command_buffer/service/texture_manager.h:22,
                 from ../../3rdparty/chromium/gpu/command_buffer/service/shared_image_factory.h:16,
                 from ../../3rdparty/chromium/components/viz/service/display/overlay_processor_on_gpu.cc:6:
../../3rdparty/chromium/ui/gl/gl_bindings.h:53:10: fatal error: GL/glxtokens.h: No such file or directory
   53 | #include <GL/glxtokens.h>
      |          ^~~~~~~~~~~~~~~~
compilation terminated.
[14673/23334] CXX obj/components/web_package/web_package/web_bundle_parser.o
[14674/23334] CXX obj/components/ui_devtools/viz/viz/surface_element.o
[14675/23334] CXX obj/components/viz/service/service/display.o
[14676/23334] CXX obj/components/ui_devtools/viz/viz/dom_agent_viz.o
ninja: build stopped: subcommand failed.