Ok, I worked it out, I'm not not using the Xcode portgroup because there
is a makefile and the Xcode portgroup doesn't play well with makefiles.
But now I'm back to my starting problem, where 3.2.5 won't build on 10.14
which is the system I'm developing on.
Yes, on Xcode 10 or later I think we need to use `-derivedData`. We should
do that in the xcode portgroup, and ports that invoke `xcodebuild`
manually would have to add that as well.
The question is: is there a good reason why the iTerm2 port should use
that Makefile? It looks like almost all of what the Makefile does is of
use only to the developer, not to us. Literally all it's doing in the
build phase (the `Deployment` target) is
xcodebuild -parallelizeTargets -target iTerm2 -configuration
Deployment && \
chmod -R go+rX build/Deployment
and the destroot phase (the `install` target) is just:
cp -R build/Deployment/iTerm2.app $(APPS)
It should be extremely easy to replace that with the xcode portgroup, and
then you'd automatically get the benefit of any improvement made to that