Xcode configuration woes

[Vincent Habchi]

Ryan,

> I don't know why Apple is doing this to us. This contradicts what we previously knew about how SDKs were meant to function. The SDKs are supposed to be the same as the system headers of a particular version. We may want to file a bug report with Apple about this. Maybe then they will fix it in a future version of Mojave.

Do you want to proceed as a member of the Apple team, or do you prefer me to do so?

> Unless you do have /usr/include on your system. Do you? For users who have installed /usr/include using the hidden installer package, you might need to have the port set configure.sdkroot to the path of the SDK, even when MacPorts wouldn't otherwise have done so.

Yes, I do. I was not even aware I shouldn’t. TBH, I don’t even remember using a “hidden” installer package. 
I will follow your advice and set configure.sdkroot in macports.conf

Thanks for your help, Ryan, as always!

Vincent