SwiftEmitModule normal arm64 Emitting module for YogaKit (in target 'YogaKit' from project 'Pods') – React native

Check Xcode config for PROJECT and Pods:

Or check directly the project.pbxproj file, you should have something like this for release or debug project configs:

83CBBA211A601CBA00E9B192 /* Release */ = {
        isa = XCBuildConfiguration;
        baseConfigurationReference = 191954F424AC5C2600989E18 /* Config.xcconfig */;
// ....
 "EXCLUDED_ARCHS[sdk=iphonesimulator*]" = "i386";

and for Pods:

"EXCLUDED_ARCHS[sdk=iphonesimulator*]" = "arm64 i386";
/* for Pods-PSG.debug.xcconfig or Pods-PSG.release.xcconfig */

Having this config should allow Intel x86_64 based builds for simulators to avoid that error.

My Podfile has also that setting:

post_install do |installer|
  flipper_post_install(installer)

  react_native_post_install(installer)
  __apply_Xcode_12_5_M1_post_install_workaround(installer)
  
  // arm64 simulator EXCLUDED_ARCHS setting:
  installer.pods_project.build_configurations.each do |config|
    config.build_settings["EXCLUDED_ARCHS[sdk=iphonesimulator*]"] = "arm64"
  end

  installer.pods_project.targets.each do |target|
    target.build_configurations.each do |config|
      config.build_settings['IPHONEOS_DEPLOYMENT_TARGET'] = '13.0'
    end
  end
end

Notes:

1. The above Podfile code was tested for RN 0.66 and RN 0.69
2. The above was tested on X86_64 architectures. Please observe it targets only the simulators to exclude some unsupported libraries for current architecture. For M1 you need to check what are the architectures to be excluded and adjust Xcode and/or Podfile settings accordingly.

You could also use some code to detect current architecture and exclude the ones that are not supported:

       #!/usr/bin/env ruby
       require 'xcodeproj'
       
       project = Xcodeproj::Project.open 'Foobar.xcodeproj'
       
       bad_arch = 'arm64'
       current_arch = `uname -m`.strip
       
       # xcode 12 on non-arm64 needs to exclude it for debug simulator builds so that we can test
       if current_arch != bad_arch
         project.build_settings('Debug')["EXCLUDED_ARCHS[sdk=iphonesimulator*]"] = bad_arch
         project.save
       end

Source of above Podfile code:
https://www.reddit.com/r/swift/comments/mw8djk/comment/gvi1rzh