Cannot install brew on Mojave with Xcode 10

Question

I can not install any brew packages on my mac with the following error info.

Installed on my Mac:

• macOS 10.14 Beta (18A293u)
• Xcode 9.3 (9E145)
• Xcode 10.0 beta (10L176w)

Type in brew install xxx. The output is:

Error: Your Xcode (9.3) is too outdated.
Please update to Xcode 10.0 (or delete it).
Xcode can be updated from
https://developer.apple.com/download/more/

Error: Xcode alone is not sufficient on Mojave.
Install the Command Line Tools:
xcode-select --install

But as I type in xcode-select --install, it says it is not available
Xcode select install error

Paths of two versions of Xcode on my Mac:

/Applications/Xcode-beta.app
/Applications/Xcode.app

And my config output:
xcode-select -p

/Applications/Xcode.app/Contents/Developer     

brew config

HOMEBREW_VERSION: 1.6.7
ORIGIN: https://github.com/Homebrew/brew
HEAD: 22e9fd772926e389e264cfb328c3d810b06759f9
Last commit: 5 days ago
Core tap ORIGIN: https://github.com/Homebrew/homebrew-core
Core tap HEAD: 854bb90b366169915849fc9a83e941b8883cea1f
Core tap last commit: 6 hours ago
HOMEBREW_PREFIX: /usr/local
CPU: octa-core 64-bit haswell
Homebrew Ruby: 2.3.6 =>./System/Library/Frameworks/Ruby.framework/Versions/2.3/usr/bin/ruby
Clang: 9.1 build 902
Git: 2.15.1 => /Applications/Xcode.app/Contents/Developer/usr/bin/git
Curl: 7.54.0 => /usr/bin/curl
Java: 1.8.0_131
macOS: 10.14-x86_64
CLT: N/A
Xcode: 9.3
XQuartz: N/A

Answer 1

You will need to install both "Xcode 10.0 Beta" from https://developer.apple.com/download/ AND "Command Line Tools (macOS 10.14) for Xcode 10 Beta" from

https://download.developer.apple.com/Developer_Tools/Command_Line_Tools_macOS_10.14_for_Xcode_10/Command_Line_Tools_macOS_10.14_for_Xcode_10.dmg

Update contributed by other comments, after you installed "Command Line Tools", you will also need to execute the following command in your terminal.

open /Library/Developer/CommandLineTools/Packages/macOS_SDK_headers_for_macOS_10.14.pkg