Feat/ios m1 improvements (#32296)

Summary:
* Remove left over from a1c445a#commitcomment-57240925
* Add a warning if running with Rosetta2 as per #32284 (comment)

## Changelog

[iOS] [Fixed] - Removed __apply_Xcode_12_5_M1_post_install_workaround
[iOS] [Changed] - Warn if Rosetta2 is being used (x86_64 on arm64)

Pull Request resolved: #32296

Test Plan: Build on macOS Apple devices without any warnings during `pod install`

Reviewed By: RSNara

Differential Revision: D31291567

Pulled By: fkgozali

fbshipit-source-id: 65e54507dedcdba39c1b441aad85e940eedc8b52

Author: barbieri

scripts/react_native_pods.rb

@@ -16,6 +16,13 @@ def use_react_native! (options={})
   # Include Hermes dependencies
   hermes_enabled = options[:hermes_enabled] ||= false
 
+  if `/usr/sbin/sysctl -n hw.optional.arm64 2>&1`.to_i == 1 && !RUBY_PLATFORM.start_with?('arm64')
+    Pod::UI.warn 'Do not use "pod install" from inside Rosetta2 (x86_64 emulation on arm64).'
+    Pod::UI.warn ' - Emulated x86_64 is slower than native arm64'
+    Pod::UI.warn ' - May result in mixed architectures in rubygems (eg: ffi_c.bundle files may be x86_64 with an arm64 interpreter)'
+    Pod::UI.warn 'Run "env /usr/bin/arch -arm64 /bin/bash --login" then try again.'
+  end
+
   # The Pods which should be included in all projects
   pod 'FBLazyVector', :path => "#{prefix}/Libraries/FBLazyVector"
   pod 'FBReactNativeSpec', :path => "#{prefix}/React/FBReactNativeSpec"

template/ios/Podfile

@@ -25,6 +25,5 @@ target 'HelloWorld' do
 
   post_install do |installer|
     react_native_post_install(installer)
-    __apply_Xcode_12_5_M1_post_install_workaround(installer)
   end
 end