GL/glew.h not found error when building software

Question

I am attempting to build a bit of software that uses GLEW. But I've found this issue exists whenever I try to build any program that uses GLEW.

Remarkably I've installed glew and can confirm that the h file it's complaining about is there. As far as I know, /usr/local/include is one of the places gcc will look, right?

$ test -e /usr/local/include/GL/glew.h
$ echo $?  # 0 means file exists
0
$ cmake .
-- Configuring done
-- Generating done
-- Build files have been written to: ...
$ make
[ 14%] Building CXX object CMakeFiles/.../Main.cpp.o
In file included from ...Main.cpp:6:
...Main.hpp:10:10: fatal error:
      'GL/glew.h' file not found
#include <GL/glew.h>
         ^~~~~~~~~~~
1 error generated.
...

Any ideas what steps I can start to take to address this problem?

Does anyone know how this is even possible?

BTW the CMakeLists.txt of this particular program simply uses link_libraries(GLEW GL GLU glut)