Hi I'm using Xcode Version 12.0 beta 3 (12A8169g). Valid architectures in build settings is missing. Does anybody know how to add valid architectures in XCode 12.0 version. XCode is taking care of it or is it a beta version bug.

Hi I'm using Xcode Version 12.0 beta 3 (12A8169g). Valid architectures in build settings is missing. Does anybody know how to add valid architectures in XCode 12.0 version. XCode is taking care of it or is it a beta version bug.

From Xcode 12 release notes:
The Build Settings editor no longer includes the Valid Architectures build setting (VALID_ARCHS), and its use is discouraged. Instead, there is a new Excluded Architectures build setting (EXCLUDED_ARCHS). If a project includes VALID_ARCHS, the setting is displayed in the User-Defined section of the Build Settings editor.
I changed the value for this setting to true instead and it worked for me:
Build Active Architecture Only
https://developer.apple.com/documentation/xcode-release-notes/xcode-12-release-notes .
Deprecations
The Build Settings editor no longer includes the Valid Architectures build setting (VALID_ARCHS), and its use is discouraged. Instead, there is a new Excluded Architectures build setting (EXCLUDED_ARCHS). If a project includes VALID_ARCHS, the setting is displayed in the User-Defined section of the Build Settings editor. (15145028)
The legacy build system is deprecated, and will be removed in a future release. (62742902)