git clone https://github.com/tesseract-ocr/tesseract/
cd tesseract
./autogen.sh
mkdir build
cd build

Optionally add CXX=g++-8 to the configure command if you really want to use a different compiler.

../configure PKG_CONFIG_PATH=/usr/local/opt/icu4c/lib/pkgconfig:/usr/local/opt/libarchive/lib/pkgconfig:/usr/local/opt/libffi/lib/pkgconfig
make -j

Optionally install Tesseract.

sudo make install

Optionally build and install training tools.

make training
sudo make training-install