Xcode configuration woes

[Vincent Habchi]

Ryan,

> Yup, NSAppearanceNameDarkAqua is new in macOS 10.14.
[…]

> So you must be on macOS 10.13 with Xcode 10.

Unfortunately not : 
> uname -a
Darwin Air.local 18.2.0 Darwin Kernel Version 18.2.0: Sat Nov  3 12:30:49 PDT 2018; root:xnu-4903.231.1~11/RELEASE_X86_64 x86_64

As you can see, I even run a beta of 10.14.2.

Air > ls -l /System/Library/Frameworks/AppKit.framework/Versions/Current/
total 43720
-rwxr-xr-x    1 root  wheel  47503104  4 Nov 09:31 AppKit
-rw-r--r--    1 root  wheel    309176 25 Jul 18:33 AppKit.tbd
drwxr-xr-x  259 root  wheel      8288 25 Jul 18:33 Headers
drwxr-xr-x    3 root  wheel        96 25 Jul 18:33 Modules
drwxr-xr-x   77 root  wheel      2464  7 Nov 22:57 Resources
drwxr-xr-x    8 root  wheel       256 21 Sep 05:59 XPCServices
drwxr-xr-x    3 root  wheel        96  7 Nov 22:57 _CodeSignature

Air > ls -l /System/Library/Frameworks/AppKit.framework/Versions/Current/Headers/
total 1328
-rw-r--r--  1 root  wheel  301352 15 Mar  2018 AppKit.apinotes
-rw-r--r--  1 root  wheel    8613 15 Mar  2018 AppKit.h
-rw-r--r--  1 root  wheel    1920 15 Mar  2018 AppKitDefines.h
[…]

All headers here are dated 15 Mars 2018, and are obviously 10.13 versions.

I have Xcode 10.1 installed, and:

Air > xcode-select --install
xcode-select: error: command line tools are already installed, use "Software Update" to install updates

Weird, no?

Vincent