Reference: xmlsec/python-xmlsec#254 (comment)
- Remove the official formula
brew uninstall libxmlsec1
- Download the last known good formula and shove it into /tmp
export DESIRED_SHA="7f35e6ede954326a10949891af2dba47bbe1fc17"
wget -O /tmp/libxmlsec1.rb "https://raw.githubusercontent.com/Homebrew/homebrew-core/${DESIRED_SHA}/Formula/libxmlsec1.rb"
- Install the local copy of the last known good formula from /tmp
brew install --formula /tmp/libxmlsec1.rb