Starting on macOS 11, the dynamic loader has a builtin cache of
system-provided dylib files. They do not actually exist on the
filesystem. However, runtime dependencies recorded in Mach-O binaries
can still have `LC_LOAD_DYLIB` entries referring to such dylib files by
absolute path. The dynamic loader simply resolves the paths from its
cache. Teach `file(GET_RUNTIME_DEPENDENCIES)` to skip dependencies on
such dylib paths. For practical software distribution purposes they do
not exist, or at least can be assumed available on all deployments.
Issue: #20863
Provide a standardized way to handle the C++ "standard" headers
customized to be used with current CMake C++ standard constraints.
Offer under directory `cm` headers which can be used as direct
replacements of the standard ones. For example:
#include <cm/string_view>
can be used safely for CMake development in place of the `<string_view>`
standard header.
Fixes: #19491
