Error: xcrun: error: invalid active developer path (/Library/Developer/CommandLineTools), missing xcrun at: /Library/Developer/CommandLineTools/usr/bin/xcrun
Solution: xcode-select --install
Error: Warning: /usr/local/Frameworks isn't writable.
This can happen if you "sudo make install" software that isn't managed by by Homebrew. If a formula tries to write a file to this directory, the install will fail during the link step.
Solution:
chown -R whoami /usr/local/*