[UserProjectIntegrator] Allows the use of the `GCC_PREPROCESSOR_DEFINITION` flag…

[UserProjectIntegrator] Allows the use of the `GCC_PREPROCESSOR_DEFINITION` flag `${inherited}`  without emitting a warning

Closes https://github.com/CocoaPods/CocoaPods/issues/2577

CHANGELOG.md

@@ -11,6 +11,11 @@ To install or update CocoaPods see this [guide](http://docs.cocoapods.org/guides
   [Samuel Giddins](https://github.com/segiddins)
   [#2470](https://github.com/CocoaPods/CocoaPods/issues/2470)
 
+* Allows the use of the `GCC_PREPROCESSOR_DEFINITION` flag `${inherited}`
+  without emitting a warning.  
+  [Samuel Giddins](https://github.com/segiddins)
+  [#2577](https://github.com/CocoaPods/CocoaPods/issues/2577)
+
 ##### Bug Fixes
 
 * Improved sanitizing of configuration names to avoid generating invalid

lib/cocoapods/installer/user_project_integrator.rb

@@ -144,7 +144,7 @@ module Pod
               if xcconfig
                 xcconfig.to_hash.keys.each do |key|
                   target_value = config.build_settings[key]
-                  if target_value && !target_value.include?('$(inherited)')
+                  if target_value && target_value !~ /\$[({]inherited[})]/
                     print_override_warning(aggregate_target, user_target, config, key)
                   end
                 end

spec/unit/installer/user_project_integrator_spec.rb

@@ -70,6 +70,20 @@ module Pod
             'overrides the `GCC_PREPROCESSOR_DEFINITIONS` build setting'
         end
 
+        it 'allows the use of the alternate form of the inherited flag' do
+          UI.warnings = ''
+          target_config = stub(:name => 'Release', :build_settings => { 'GCC_PREPROCESSOR_DEFINITIONS' => 'FLAG=1 ${inherited}' })
+          user_target = stub(:name => 'SampleProject', :build_configurations => [target_config])
+          @library.stubs(:user_targets).returns([user_target])
+
+          @library.xcconfigs['Release'] = { 'GCC_PREPROCESSOR_DEFINITIONS' => 'COCOAPODS=1' }
+          @integrator = UserProjectIntegrator.new(@podfile, config.sandbox, temporary_directory, [@library])
+
+          @integrator.unstub(:warn_about_xcconfig_overrides)
+          @integrator.send(:warn_about_xcconfig_overrides)
+          UI.warnings.should.not.include 'GCC_PREPROCESSOR_DEFINITIONS'
+        end
+
         it 'allows build settings which inherit the settings form the CocoaPods xcconfig' do
           UI.warnings = ''
           target_config = stub(:name => 'Release', :build_settings => { 'GCC_PREPROCESSOR_DEFINITIONS' => 'FLAG=1 $(inherited)' })