[tex-live] Platform & library check on macOS during TL 2018 installation

[Karl Berry]

    Dear Norbert,

Norbert is not the only one who works on the installer :).

    would it be possible for the
    installer to check if the system is darwin10, and if so, check whether
    libc++ is present on the system, and if not, print an error saying
    that it cannot proceed unless the user installs the library?

Anything is possible. The question is, how do we check whether libc++ is
present? We can't try to link with it, that would lead to far more
complications. What file location(s) should we check?

I assume checking for "darwin10" means checking that
sw_vers -productVersion returns 10.10?

    We have various options in principle:

I agree that all of these other options are worse, except perhaps simply
giving up.  I find these constantly proliferating special cases for Macs
highly unfortunate. -k