Problems with not finding Framework header files on Mojave 10.14.6

[Joshua Root]

Greg Earle wrote:
> I have Xcode 10.3 installed on it (to ensure it installed the 10.14.6 
> SDK).

Xcode 11 should also be OK as long as you have the Command Line Tools
installed, which will provide the 10.14 SDK.

> Warning: The macOS 10.14 SDK does not appear to be installed. Ports may 
> not build correctly.

This warning is generated by this code:
<https://github.com/macports/macports-base/blob/master/src/port1.0/portutil.tcl#L3376>

It's triggered by the SDK that was found not being called
"MacOSX10.14.sdk". We always try to use an SDK with the version in its
name if at all possible, since we don't know which version "MacOSX.sdk"
actually is.

On my 10.14 system, this is the situation in the CLTs' SDKs directory:

% ls -l /Library/Developer/CommandLineTools/SDKs/MacOSX10.14.sdk
lrwxr-xr-x  1 root  wheel  10  4 Oct 13:30
/Library/Developer/CommandLineTools/SDKs/MacOSX10.14.sdk -> MacOSX.sdk

i.e. MacOSX10.14.sdk exists as a symlink.

The log likely contains more relevant information; please post the whole
thing to a pastebin so we can take a look.

- Josh