Ensuring that all dirs in LDFLAGS exist is only needed for Ruby due to its `configure` requirements.
If some LDFLAGS entries point to a nonexisting path to which the user doesn't have permission. this causes a build failure.
To support building for Apple ARM64 which was introduced in MacOS 11
OpenSSL added support for Apple ARM in 1.1.1
(61168b5b8d).
Python added support for MacOS 11 in 3.7.8+, 3.8.4+, 3.9.0+
(https://github.com/python/cpython/pull/21113 and backports).