message: update docs to gcc-5
  Summary: See
diff: @@ -78,7 +78,7 @@ cd redex
  Now, build ReDex using autoconf and make.
  ```
  -# if you're using gcc, please use gcc-4.9
  +# if you're using gcc, please use gcc-5
  autoreconf -ivf && ./configure && make -j4
  sudo make install
  ```
  