Make system gcc/g++ the default c/c++ compiler for brew.

add_sys-gcc-link_to_brew-bin.sh

#!/usr/bin/env -S bash -euECo pipefail
# based on https://gist.github.com/alghanmi/8853646
#
# Make system gcc tools the default compiler for brew.
#	brew installs gcc-4.8, but does not create symlinks for it to be used
#	without the version number.
#	This script:
#		1. Generate symlinks for all gcc tools installed with system package manager.
#		2. 
#
# How to apply.
# curl -LkfgSs -O https://gist.github.com/aachyee/4ad91190323de96091ff23359d172415/raw/add_sys-gcc-link_to_brew-bin.sh
# bash -n ./add_sys-gcc-link_to_brew-bin.sh # option '-nv' for more info.
# shellcheck 
# bash ./add_sys-gcc-link_to_brew-bin.sh

#Make sure brew is installed
#type -P brew &>/dev/null || { echo "brew is not installed."; exit 1; }

echo -n 'installed brew version: '
brew --version
echo -n 'installed gcc version: '
gcc -v | grep version

BREW_BASE="$(brew --prefix)"
BREW_BIN="${BREW_BASE}/bin"
BREW_SBIN="${BREW_BASE}/sbin"
PATH_WO_BREW_BINS=$(sed -E "/${BREW_BIN}|${BREW_SBIN}//g;s/::+/:/g;s/^:|:$//g"<<<${PATH})

# GCC_VER=$(readlink -f "$(find ${PATH_WO_BREW//:/\/ } -maxdepth 1 -regextype posix-extended -iregex '.*/gcc$' | sort | tail -n1)" | grep -oE '[0-9.]+$')
GCC_VER=$(readlink -f $(which gcc)| grep -oE '[0-9.]+$')
GCC_CMDS='cc gcc c++ cpp g++ gcc-ar gcc-nm gcc-ranlib gcov gcov-dump gcov-tool lto-dump'
#   'gcc-# c++-# cpp-# g++-# gcc-ar-# gcc-nm-# gcc-ranlib-# gcov-# gcov-dump-# gcov-tool-# lto-dump-#'

#Generate Symlinks 
cd $BREW_BIN
for cmd in $GCC_CMDS
do
  LN_NAME=$(echo $app | sed 's/\(.*\)-4.8/\1/')
  ln -s $cmd $LN_NAME
done

#Prepend brew's path to $PATH
#echo '#Making brew apps the first in your path' >> ~/.bash_profile
#echo 'PATH=$(brew --prefix)/bin:$PATH' >> ~/.bash_profile
echo 'add "PATH=$(brew --prefix)/bin:$PATH" to "~/.bash_profile".