Matlab R2015b and Xcode 7 - Problem Number 2

Hello I have a problem using the mex function with R2015b and Xcode 7. Specifically I first had the issue described in:

http://uk.mathworks.com/matlabcentral/answers/243868-mex-can-t-find-compiler-after-xcode-7-update-r2015b#comment_311027

where the compiler could not be found, I followed the instructions and then I get the error:

Building with 'Xcode Clang++'. Error using mex clang: error: invalid deployment target for -stdlib=libc++ (requires OS X 10.7 or later)

I tried to fix it by modifying the lines:

CC='xcrun -sdk macosx10.11 clang'

MW_SDKROOT_TMP="find `xcode-select -print-path` -name MacOSX10.11.sdk"

MACOSX_DEPLOYMENT_TARGET='10.11'

CXX='xcrun -sdk macosx10.11 clang++'

in the file mexopts.sh located in /Applications/MATLAB_R2015b.app/bin

I also deleted the mexopts.sh, clang_maci64.xml, clang++_maci64.xml files located in [prefdir 'mex_c_maci64.xml'] but the problem persists. Any suggestions?