所以，我正在使用 freeglut 尝试做一些 openGL 的东西，但我不断收到错误，说引用未定义：
"C:\Program Files (x86)\JetBrains\CLion 2016.2.1\bin\cmake\bin\cmake.exe" --build C:\Users\Nick\.CLion2016.2\system\cmake\generated\cs455opengl-9b23e7f0\9b23e7f0\Debug --target all -- -j 4
Scanning dependencies of target cs455openGL
[ 50%] Building CXX object CMakeFiles/cs455openGL.dir/main.cpp.obj
[100%] Linking CXX executable cs455openGL.exe
CMakeFiles\cs455openGL.dir/objects.a(main.cpp.obj): In function `Z4initv':
C:/Users/Nick/ClionProjects/cs455opengl/main.cpp:12: undefined reference to `glClearColor@16'
C:/Users/Nick/ClionProjects/cs455opengl/main.cpp:13: undefined reference to `glMatrixMode@4'
C:/Users/Nick/ClionProjects/cs455opengl/main.cpp:14: undefined reference to `glLoadIdentity@0'
C:/Users/Nick/ClionProjects/cs455opengl/main.cpp:15: undefined reference to `glOrtho@48'
CMakeFiles\cs455openGL.dir/objects.a(main.cpp.obj): In function `Z7displayv':
C:/Users/Nick/ClionProjects/cs455opengl/main.cpp:20: undefined reference to `glClear@4'
C:/Users/Nick/ClionProjects/cs455opengl/main.cpp:21: undefined reference to `glColor3f@12'
C:/Users/Nick/ClionProjects/cs455opengl/main.cpp:22: undefined reference to `glVertex3f@12'
C:/Users/Nick/ClionProjects/cs455opengl/main.cpp:23: undefined reference to `glVertex3f@12' …