In Dave's case, he's running a perl script and not building with a compiler -
so it's not CPPFLAGS but rather @INC changes with perl 5.26 that he's seeing.
As always, changes are described in perldelta:
> On Mar 6, 2018, at 4:00 AM, Ryan Schmidt <ryandes...@macports.org> wrote:
> On Mar 5, 2018, at 22:09, Ryan Schmidt wrote:
>> On Mar 5, 2018, at 20:06, Dave Horsfall wrote:
>>> A script that I wrote and has worked fine for ages is now breaking with:
>>> Can't locate Scanner.pm in @INC (you may need to install the Scanner
>>> module) (@INC contains:
>>> /opt/local/lib/perl5/5.26) at ./uniscan.pl line 40.
>>> BEGIN failed--compilation aborted at ./uniscan.pl line 40.
>>> That "Scanner.pm" module is one I wrote myself, and it's definitely there.
>>> No, I haven't changed anything, and it works just fine on my FreeBSD (5.24)
>>> and Penguin (5.20) boxes. Older Mac versions of Perl also work (5.16,
>>> 5.22, 5.24).
>>> Rebooted (ugh!) to eliminate a corrupted image in swap: nope.
>>> Uninstalled and reinstalled in case the disk binary was corrupt: nope.
>>> Don't tell me that Perl 5.26 comes with a built-in time-bomb...
>> Add -I to CPPFLAGS. Perl < 5.26 did so automatically, but 5.26 no longer
> I meant: -I.
>> See for example
Daniel J. Luke