問題描述：
編譯安裝eigen，cmake時遇到如下問題：
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}
-- Configuring incomplete, errors occurred!
系統環境：
ubuntu16.04
解決方案：
執行：
sudo apt-get install libxmu-dev
![sudo apt-get update 出錯 Updating from such a repository can‘t be done securely, and is therefore[圖]](data:image/gif;base64,R0lGODlhAQABAIAAAP///wAAACwAAAAAAQABAAACAkQBADs=)