The following error occurred:

Attempt #1

Install CLI tools

xcode-select --install

Locate SDK path

xcrun --show-sdk-path

Create symbolic link

sudo ln -s /Library/Developer/CommandLineTools/SDKs/MacOSX10.14.sdk/usr/include /usr/include

Attempt #2

Install Xcode

https://itunes.apple.com/nl/app/xcode/id497799835

Create symbolic link

sudo ln -s /Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX10.14.sdk/usr/include /usr/include

Attempt #3

sudo installer -pkg /Library/Developer/CommandLineTools/Packages/macOS_SDK_headers_for_macOS_10.14.pkg -target /