1. Install most recent gcc version
$ sudo port install gcc48
$ sudo port select --set gcc mp-gcc48
2. Install most recent clang version
$ sudo port install clang-3.6
$ sudo port select --set clang mp-clang-3.6
3. Export variables holding the patch to C and C++ compiler
$ export CC=/opt/local/bin/clang
$ export CXX=/opt/local/bin/clang++