Error installing Root 6 on Mac OS Sierra with Xcode 8

ROOT
7

gcc 4.9 is fine. Anyway, you have to tell ROOT to use the 4.9 version.

Where did you install it? If you installed 4.9 in /usr/local/bin, try for example to type this before running cmake:

[code]unset CPLUS_INCLUDE_PATH
export PATH=/usr/local/bin:$PATH
export LD_LIBRARY_PATH=/usr/local/lib/:$LD_LIBRARY_PATH

alias gcc=‘gcc-4.9’
alias cc=‘gcc-4.9’
alias g++=‘g+±4.9’
alias c++=‘c+±4.9’[/code]

And / or:

cmake -DCMAKE_CXX_COMPILER=/usr/local/bin/g++-4.9 -DCMAKE_C_COMPILER=/usr/local/bin/gcc-4.9 -DCMAKE_Fortran_COMPILER=/usr/local/bin/gfortran-4.9 ../root

Check these here below, there are some extra options you may need to use:
stackoverflow.com/questions/2897 … a-homebrew
apple.stackexchange.com/question … c-compiler