无法在R中安装'ks'包

Question

我正在使用R 3.0.2和RStudio 0.98.945 for Mac。

加载'ks'包会出现此错误消息。

Loading required package: rgl
Error : .onLoad failed in loadNamespace() for 'rgl', details:
  call: dyn.load(file, DLLpath = DLLpath, ...)
  error: unable to load shared object          
'/Library/Frameworks/R.framework/Versions/3.0/Resources/library/rgl/libs/rgl.so':
  dlopen(/Library/Frameworks/R.framework/Versions/3.0/Resources/library/rgl/libs/r    gl.so, 6): Library not loaded: /usr/X11/lib/libGLU.1.dylib
  Referenced from:     /Library/Frameworks/R.framework/Versions/3.0/Resources/library/rgl/libs/rgl.so
  Reason: image not found
Error: package ‘rgl’ could not be loaded

加载'rgl'包会出现相同的错误消息。

我该如何解决这个问题？