Error: The following directories are not writable by your user:
/usr/local/include
/usr/local/share/man/man3
/usr/local/share/man/man5
/usr/local/share/man/man7
/usr/local/share/man/man8
You should change the ownership of these directories to your user.
To resolve try:
sudo chown -R $(whoami) /usr/local/include /usr/local/share/man/man3 /usr/local/share/man/man5 /usr/local/share/man/man7 /usr/local/share/man/man8
If that fails, just reinstall brew by going to https://brew.sh/
/usr/bin/ruby -e "$(curl -fsSL https://raw.githubusercontent.com/Homebrew/install/master/install)"