Answering part of my own question here using the rawhide test instance:

$ pkg-config --libs glew
-lGLEW -lGLU -lGL

Minimal CMake test config:

$ cmake .
-- GLEW_LIBRARIES: /usr/lib64/libGLEW.so
-- Configuring done
-- Generating done

It looks like -lGLU is being picked up somewhere else in the build but not -lGL...

Thanks,
Richard