$ brew install zlib $ xcode-select --install xcode-select: note: install requested for command line developer tools $ sudo installer -pkg /Library/Developer/CommandLineTools/Packages/macOS_SDK_headers_for_macOS_10.14.pkg -target / installer: Package name is macOS_SDK_headers_for_macOS_10.14 installer: Installing at base path / installer: The install was successful. $ pyenv install 3.7.3