配置Opengl时cmake报错

参考编译安装cmake时遇到的问题 GLUT_Xmu_LIBRARY (ADVANCED)
系统环境：Ubuntu16.04
在kdevelop中构建程序时cmake报错，错误信息如下：

    CMake Error: The following variables are used in this project, but they are set to NOTFOUND.

    Please set them or make sure they are set and tested correctly in the CMake files:

    GLUT_Xmu_LIBRARY (ADVANCED)

    linked by target "openglsupport" in directory {
   
   $PATH}