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