Using Mex with MATLAB_R2014b & Xcode7.0(Mac OS X 10.11)

I want to use mex in my matlab, but when I run this command:

mex -setup

Then I get

Error using mex
No supported compiler or SDK was found. For options, visit 
http://www.mathworks.com/support/compilers/R2014b/maci64.html.

My Xcode version is 7.0, and OS X version is 10.11. What should I do if I want to solve the problem?

[Tongzhou Mu]

I have already found a solution for this problem, please look at this: http://www.mathworks.com/matlabcentral/answers/246507-why-can-t-mex-find-a-supported-compiler-in-matlab-r2015b-after-i-upgraded-to-xcode-7