macOS builds should only use dependencies built via the obs-deps
build scripts. Default variants of the same dependencies are not
compatible with our app packaging requirements and thus will create
issues when creating the app bundle.
This is specifically an issue when MbedTLS is installed via Homebrew
which ships a CMake package config by default and is picked up
by our code ever since we switched to prefer CMake packages.
Creation of Info.plist files through Xcode is more canonical and
future-proof, as it will automatically pick up changes/updates
introduced by Apple. Non-standard keys can still be added via a
template file, which will then be extended by Xcode with the default
keys.
Include guards ensure that bootstrap includes happen only once for the
entire project. Moving all policy changes into an included file without
its own policy scope ensures that the policy is applied to the project.
PatTheMav