erlang_crypto_fix_below_version_20.sh

#!/usr/bin/env sh
#===========================================================================================#
#  This script is a workaround for compiling Erlang with crypto below version 20 via kerl   #
#                                                                                           #
#  The need for this script came about because newer versions of OpenSSL are not            #
#  properly detected by the compiler when choosing an Erlang version under 20;              #
#  most distros have an openssl 1.0 compatibility package in their package managers,        #
#  but I have found them unreliable at best, when it comes to compiling Erlang              #
#                                                                                           #
#  The script will download the OpenSSL source code for version 1.0.2 to $HOME/openssl,     #
#  and after compiling with the appropiate flags, it will install the resulting binary      #
#  into .openssl-1.0                                                                        #
#                                                                                           #
#  After executing the script, the environment variable KERL_CONFIGURE_OPTIONS will be      #
#  set, and its value will be output to the console. Future executions of the script will   #
#  only set the environment variable and output the same message. If for some reason        #
#  you want to recompile OpenSSL, it is enough to delete the $HOME/.openssl-1.0 folder      #
#===========================================================================================#
HOME_PATH_WITHOUT_SLASH=$(echo $HOME | cut -c2-)
SSL_SHORT_PATH="$HOME/.openssl-1.0"
SSL_FULL_PATH="$SSL_SHORT_PATH/__result/$HOME_PATH_WITHOUT_SLASH/.openssl-1.0"
export KERL_CONFIGURE_OPTIONS="--enable-debug --enable-shared-zlib --enable-dynamic-ssl-lib --enable-hipe --enable-sctp --enable-smp-support --enable-threads --enable-kernel-poll --enable-wx --with-ssl=$SSL_FULL_PATH"

cd $HOME
if [ ! -d "$HOME/openssl" ]; then
  git clone http://github.com/openssl/openssl.git --branch OpenSSL_1_0_2-stable
fi
if [ ! -d "$SSL_SHORT_PATH" ]; then
  cd openssl
  ./config --prefix="$SSL_SHORT_PATH" shared zlib -fPIC
  make depend
  make
  make install INSTALL_PREFIX="$SSL_SHORT_PATH/__result"
fi
clear

echo "Now you can compile Erlang normally with kerl or asdf"
echo "If you need to compile Erlang again, you can rerun this script, or just run the following command:"
echo "export KERL_CONFIGURE_OPTIONS=\"${KERL_CONFIGURE_OPTIONS}\""