GlutApplication fails to build.

[ghost]

GlutApplication is unable to locate freeglut headers when glut headers are not in system or mingw include directory

[mosra]

GLUT finding routine is part of CMake, thus I don't think this issue is related to Magnum. If you have GLUT installed in "non-standard" location (e.g. C:/Program Files), CMake would not able to find it without hint, as no info about installation location is provided by GLUT in the registry or anywhere else. The FindGLUT.cmake file (which takes care of finding the GLUT library) accepts undocumented GLUT_ROOT_PATH variable, with which you can specify the install location. In general it's always possible to manually specify the paths using cmake-gui, if everything else fails.