I'm trying to install QGIS by following the instructions in from this answer (using homebrew).
I get the following error:
$ brew install osgeo/osgeo4mac/qgis3
==> Installing qgis3 from osgeo/osgeo4mac
==> Tapping brewsci/bio
Cloning into '/usr/local/Homebrew/Library/Taps/brewsci/homebrew-bio'...
remote: Enumerating objects: 226, done.
remote: Counting objects: 100% (226/226), done.
remote: Compressing objects: 100% (223/223), done.
remote: Total 226 (delta 1), reused 134 (delta 1), pack-reused 0
Receiving objects: 100% (226/226), 161.66 KiB | 0 bytes/s, done.
Resolving deltas: 100% (1/1), done.
Tapped 211 formulae (245 files, 496KB).
qt5-webkit: Must be built with `brew install --no-sandbox ...`, or install steps will fail.
qt5-webkit: A full installation of Xcode.app is required to compile this software.
Installing just the Command Line Tools is not sufficient.
Xcode can be installed from the App Store.
Error: Unsatisfied requirements failed this build.
Why is it telling me I need Xcode, and why would I need to compile qt5 to load QGIS?