message: Mention that autotools is required on macOS
diff: @@ -69,6 +69,8 @@ brew install cmake qt5
  brew link qt5 --force
  ```
  +You will also need `autotools`. That is usually available by default but might need to be explicitly installed with `brew install autotools`.
  +
  ## Android
  To build for Android, you must download components of the Android SDK, the Android NDK, and Java Development Kit.
  