feat(apple): add :build_setting_overrides to options (#2204)

`:build_setting_overrides` allows you to override build settings defined in the
final Xcode project.

ios/pod_helpers.rb

@@ -98,6 +98,12 @@ def try_pod(name, podspec, project_root)
   pod name, :podspec => podspec if File.exist?(File.join(project_root, podspec))
 end
 
+def override_build_settings!(build_settings, settings_to_append)
+  settings_to_append&.each do |setting, value|
+    build_settings[setting] = value
+  end
+end
+
 def use_hermes?(options)
   use_hermes = ENV.fetch('USE_HERMES', nil)
   return use_hermes == '1' unless use_hermes.nil?

ios/test_app.rb

@@ -259,6 +259,8 @@ def make_project!(xcodeproj, project_root, target_platform, options)
     uitests_build_settings[PRODUCT_BUNDLE_IDENTIFIER] = "#{product_bundle_identifier}UITests"
   end
 
+  override_build_settings!(build_settings, options[:build_setting_overrides])
+
   build_settings[PRODUCT_DISPLAY_NAME] = display_name
   build_settings[PRODUCT_VERSION] = version || '1.0'
 

test/test_pod_helpers.rb

@@ -112,4 +112,30 @@ def test_v
     assert_equal(1_001_000, v(1, 1, 0))
     assert_equal(1_001_001, v(1, 1, 1))
   end
+
+  def test_override_build_settings
+    build_settings = { 'OTHER_LDFLAGS' => '-l"Pods-TestApp"', 'ONLY_ACTIVE_ARCH' => 'NO' }
+
+    override_build_settings!(build_settings, {})
+
+    assert_equal('-l"Pods-TestApp"', build_settings['OTHER_LDFLAGS'])
+
+    override_build_settings!(build_settings, { 'OTHER_LDFLAGS' => ' -ObjC' })
+
+    assert_equal(' -ObjC', build_settings['OTHER_LDFLAGS'])
+
+    # Test passing a table
+    build_settings_arr = { 'OTHER_LDFLAGS' => ['$(inherited)', '-l"Pods-TestApp"'] }
+    override_build_settings!(build_settings_arr, { 'OTHER_LDFLAGS' => [' -ObjC'] })
+
+    assert_equal([' -ObjC'], build_settings_arr['OTHER_LDFLAGS'])
+
+    # Test setting a new key
+    override_build_settings!(build_settings, { 'OTHER_CFLAGS' => '-DDEBUG' })
+
+    assert_equal('-DDEBUG', build_settings['OTHER_CFLAGS'])
+    override_build_settings!(build_settings, { 'ONLY_ACTIVE_ARCH' => 'YES' })
+
+    assert_equal('YES', build_settings['ONLY_ACTIVE_ARCH'])
+  end
 end