HomeBrew is displaying the following issues while installing a dependency.
Error: The `brew link` step did not complete successfully The formula built, but is not symlinked into /usr/local Could not symlink bin/a2x /usr/local/bin is not writable. You can try again using: brew link asciidoc
Following Alex's answer I was able to resolve this issue; seems this to be an issue non specific to the packages being installed but of the permissions of
sudo chown -R `whoami`:admin /usr/local/bin
For some packages, you may also need to do this to
sudo chown -R `whoami`:admin /usr/local/share sudo chown -R `whoami`:admin /usr/local/opt