make -j4 error while building.. need help compiling about em-dosbox HOT 2 OPEN

sudo apt-get install build-essential cmake python2.7 nodejs default-jre git-core
sudo apt-get install libsdl1.2-dev libsdl1.2debian libsdl-image1.2-dev
aclocal
./autogen.sh
emconfigure ./configure
make -j4

still the same
mkdir emscr
sudo apt-get install git
sudo apt-get install nodejs
sudo apt-get install default-jre
sudo apt-get install llvm

wget http://llvm.org/releases/3.2/clang+llvm-3.2-x86-linux-ubuntu-12.04.tar.gz
gunzip clang+llvm-3.2-x86-linux-ubuntu-12.04.tar.gz
tar xvf clang+llvm-3.2-x86-linux-ubuntu-12.04.tar
git clone git://github.com/kripken/emscripten.git
echo 'edit path like this /home/sol/Desktop/emscripten/clang+llvm-3.2-x86-linux-ubuntu-12.04/bin'

hope-ing for luck

from em-dosbox.

I have been trying to follow the compiling instructions, but as a extreme beginner (will be second thing compiled) i am at a loss.

using ubuntu 18-4.
I got to emconfigure ./configure then it errors out. Cannont find SDL 1.2 or better

SDL 2 is installed

from em-dosbox.