[RN][iOS] Improve Swift support for 3rd party libs (#42075)

Author: cipolleschi

packages/react-native/ReactCommon/React-Fabric.podspec

@@ -33,7 +33,8 @@ Pod::Spec.new do |s|
   s.source                 = source
   s.source_files           = "dummyFile.cpp"
   s.pod_target_xcconfig = { "USE_HEADERMAP" => "YES",
-                            "CLANG_CXX_LANGUAGE_STANDARD" => "c++17" }
+                            "CLANG_CXX_LANGUAGE_STANDARD" => "c++17",
+                            "DEFINES_MODULE" => "YES" }
 
   if ENV['USE_FRAMEWORKS']
     s.header_mappings_dir     = './'

packages/react-native/ReactCommon/react/debug/React-debug.podspec

@@ -27,7 +27,10 @@ Pod::Spec.new do |s|
   s.source                 = source
   s.source_files           = "**/*.{cpp,h}"
   s.header_dir             = "react/debug"
-  s.pod_target_xcconfig    = { "CLANG_CXX_LANGUAGE_STANDARD" => "c++17" }
+  s.pod_target_xcconfig    = {
+    "CLANG_CXX_LANGUAGE_STANDARD" => "c++17",
+    "DEFINES_MODULE" => "YES"
+  }
 
   if ENV['USE_FRAMEWORKS']
     s.module_name            = "React_debug"

packages/react-native/ReactCommon/react/renderer/graphics/React-graphics.podspec

@@ -49,7 +49,11 @@ Pod::Spec.new do |s|
     header_search_paths = header_search_paths + ["\"$(PODS_TARGET_SRCROOT)/platform/ios\""]
   end
 
-  s.pod_target_xcconfig  = { "USE_HEADERMAP" => "NO", "HEADER_SEARCH_PATHS" => header_search_paths.join(" ") }
+  s.pod_target_xcconfig  = {
+    "USE_HEADERMAP" => "NO",
+    "HEADER_SEARCH_PATHS" => header_search_paths.join(" "),
+    "DEFINES_MODULE" => "YES"
+  }
 
   s.dependency "glog"
   s.dependency "RCT-Folly/Fabric", folly_version

packages/react-native/ReactCommon/react/utils/React-utils.podspec

@@ -44,7 +44,9 @@ Pod::Spec.new do |s|
   s.exclude_files          = "tests"
   s.pod_target_xcconfig    = {
     "CLANG_CXX_LANGUAGE_STANDARD" => "c++17",
-    "HEADER_SEARCH_PATHS" => header_search_paths.join(' ')}
+    "HEADER_SEARCH_PATHS" => header_search_paths.join(' '),
+    "DEFINES_MODULE" => "YES"
+  }
 
   if ENV['USE_FRAMEWORKS']
     s.module_name            = "React_utils"