Enable with CocoaPods :configuration (#28796)

Summary:
~~⚠️ Depends on facebook/flipper#1086 and a new Flipper release.~~
Fixes 17f025b#commitcomment-38831234

Currently user’s are being told to add a definition of the `FB_SONARKIT_ENABLED` macro and examples, including those in stock React Native templates, set this for the user by making use of a `post_install` hook in the user’s `Podfile`. This leads to confusion, fragile code [when a user’s project dir structure deviates from vanilla], and is ultimately not necessary as CocoaPods already has dedicated mechanisms to:

* specify build settings (through the `xcconfig` property);
* and selectively include certain pods only in certain build configurations (e.g. debug).

## Changelog

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[iOS] [Changed] - Entirely control Flipper being enabled through inclusion in Podfile and optionally limiting to certain build configurations using the `:configuration` directive.
Pull Request resolved: #28796

Test Plan: Tested using the changes of facebook/flipper#1086 in a new app that uses RN `master`.

Reviewed By: priteshrnandgaonkar

Differential Revision: D21449754

Pulled By: passy

fbshipit-source-id: 9ff7c7f4ffc32b364b1edd82b94e0b80c3997625

scripts/react_native_pods.rb

@@ -58,8 +58,8 @@ def use_react_native! (options={})
 end
 
 def use_flipper!(versions = {})
-  versions['Flipper'] ||= '~> 0.37.0'
-  versions['DoubleConversion'] ||= '1.1.7'
+  versions['Flipper'] ||= '~> 0.41.1'
+  versions['Flipper-DoubleConversion'] ||= '1.1.7'
   versions['Flipper-Folly'] ||= '~> 2.2'
   versions['Flipper-Glog'] ||= '0.3.6'
   versions['Flipper-PeerTalk'] ||= '~> 0.0.4'
@@ -72,7 +72,7 @@ def use_flipper!(versions = {})
   # List all transitive dependencies for FlipperKit pods
   # to avoid them being linked in Release builds
   pod 'Flipper', versions['Flipper'], :configuration => 'Debug'
-  pod 'Flipper-DoubleConversion', versions['DoubleConversion'], :configuration => 'Debug'
+  pod 'Flipper-DoubleConversion', versions['Flipper-DoubleConversion'], :configuration => 'Debug'
   pod 'Flipper-Folly', versions['Flipper-Folly'], :configuration => 'Debug'
   pod 'Flipper-Glog', versions['Flipper-Glog'], :configuration => 'Debug'
   pod 'Flipper-PeerTalk', versions['Flipper-PeerTalk'], :configuration => 'Debug'
@@ -96,31 +96,4 @@ def flipper_post_install(installer)
       end
     end
   end
-  file_name = Dir.glob("*.xcodeproj")[0]
-  app_project = Xcodeproj::Project.open(file_name)
-  app_project.native_targets.each do |target|
-    target.build_configurations.each do |config|
-      cflags = config.build_settings['OTHER_CFLAGS'] || '$(inherited) '
-      unless cflags.include? '-DFB_SONARKIT_ENABLED=1'
-        puts 'Adding -DFB_SONARKIT_ENABLED=1 in OTHER_CFLAGS...'
-        cflags << '-DFB_SONARKIT_ENABLED=1'
-      end
-      config.build_settings['OTHER_CFLAGS'] = cflags
-      if (config.build_settings['OTHER_SWIFT_FLAGS'])
-        unless config.build_settings['OTHER_SWIFT_FLAGS'].include? '-DFB_SONARKIT_ENABLED'
-          puts 'Adding -DFB_SONARKIT_ENABLED ...'
-          swift_flags = config.build_settings['OTHER_SWIFT_FLAGS']
-          if swift_flags.split.last != '-Xcc'
-            config.build_settings['OTHER_SWIFT_FLAGS'] << ' -Xcc'
-          end
-          config.build_settings['OTHER_SWIFT_FLAGS'] << ' -DFB_SONARKIT_ENABLED'
-        end
-      else
-        puts 'OTHER_SWIFT_FLAGS does not exist thus assigning it to `$(inherited) -Xcc -DFB_SONARKIT_ENABLED`'
-        config.build_settings['OTHER_SWIFT_FLAGS'] = '$(inherited) -Xcc -DFB_SONARKIT_ENABLED'
-      end
-      app_project.save
-    end
-  end
-  installer.pods_project.save
 end

template/ios/HelloWorld.xcodeproj/project.pbxproj

@@ -336,10 +336,6 @@
 				CLANG_ENABLE_MODULES = YES;
 				CURRENT_PROJECT_VERSION = 1;
 				ENABLE_BITCODE = NO;
-				GCC_PREPROCESSOR_DEFINITIONS = (
-					"$(inherited)",
-					"FB_SONARKIT_ENABLED=1",
-				);
 				INFOPLIST_FILE = HelloWorld/Info.plist;
 				LD_RUNPATH_SEARCH_PATHS = "$(inherited) @executable_path/Frameworks";
 				OTHER_LDFLAGS = (

template/ios/HelloWorld/AppDelegate.m

@@ -4,7 +4,7 @@
 #import <React/RCTBundleURLProvider.h>
 #import <React/RCTRootView.h>
 
-#if DEBUG
+#ifdef FB_SONARKIT_ENABLED
 #import <FlipperKit/FlipperClient.h>
 #import <FlipperKitLayoutPlugin/FlipperKitLayoutPlugin.h>
 #import <FlipperKitUserDefaultsPlugin/FKUserDefaultsPlugin.h>
@@ -27,7 +27,7 @@ @implementation AppDelegate
 
 - (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions
 {
-#if DEBUG
+#ifdef FB_SONARKIT_ENABLED
   InitializeFlipper(application);
 #endif