Support for users with older versions of Xcode that what's on the build slaves

[Mojca Miklavec]

Hi,

Recently a user issued a ticket with a problem that was most likely
triggered by using an older version of Xcode than the one used for
creating the binary package for Perl:
    https://trac.macports.org/ticket/50894

Perl does a number of configure-time checks and then hardcodes both
the compiler and the flags to be used when installing C[++] code from
CPAN.

(ROOT does something similar which I find a bit annoying at times.)

(a) One solution would be to unconditionally remove that flag for
everyone (I don't know yet what the flag does, but I would assume it
was added for some valid reason, so it would probably be desirable to
keep it for systems that support it).
(b) One solution would be to conditionally force removal of that flag
(with some weird code; I don't know what condition would be best
used).
(c) One solution would be to close the ticket as 'wontfix' and ask the
user to either:
    - upgrade Xcode
    - manually remove the flag
    - install Perl from source or simply set "buildfromsource always"
to avoid similar problems in the future

The reverse problem can actually also happen after upgrading Xcode (if
a flag would be removed from compiler and the user compiled perl
before the upgrade, installing cpan modules could then fail because
the new compiler would no longer accept the flag that was OK for the
older one).

I would be in favour of (c), but other opinions are welcome.

Mojca