(I assume you have already installed HomeBrew.)
1. Download source code
2. run ./confugre
configure: error: cannot find install-sh, install.sh, or shtool in "." "./.." "./../.."
espeak-ng links are point to /usr/share，but home brew install those files in /usr/local/share。So we need to fix the link paths.
~/code/espeak-ng/m4$ ln -sf /usr/local/share/aclocal/ltversion.m4
~/code/espeak-ng/m4$ ln -sf /usr/local/share/aclocal/ltsugar.m4