Homebrew Symlink Error

Thanks for updating your own question this helped me a lot. I fixed this issue by making all locations in /usr/local writable to group as I am already in the admin group.

To do this just use the following command

sudo chmod -R g+w /usr/local

As of High Sierra, /usr/local is no longer chown-able. The new procedure suggested in a Homebrew issue is:

sudo chown -R $(whoami) $(brew --prefix)/*

FYI: If required /usr/local subfolders (e.g. ./include or ./Frameworks) are missing, you'll have to mkdir them first

I uninstalled what homebrew had so far installed (libevent dependency):

brew uninstall libevent

Then chow-ned the usr/local directory:

sudo chown -R $(whoami) /usr/local

Then tried to install memcached again and it worked:

brew install memcached