[AggregateXCConfig] Move pod_targets in helper method

lib/cocoapods/generator/xcconfig/aggregate_xcconfig.rb

@@ -49,7 +49,6 @@ module Pod
         # @return [Xcodeproj::Config]
         #
         def generate
-          pod_targets = target.pod_targets_for_build_configuration(@configuration_name)
           config = {
             'OTHER_LDFLAGS' => '$(inherited) ' + XCConfigHelper.default_ld_flags(target),
             'PODS_ROOT' => target.relative_pods_root,
@@ -134,6 +133,21 @@ module Pod
           @xcconfig.merge!('LD_RUNPATH_SEARCH_PATHS' => ld_runpath_search_paths.join(' '))
         end
 
+        private
+
+        #---------------------------------------------------------------------#
+
+        # !@group Private Helpers
+
+        # Returns the {PodTarget}s which are active for the current
+        # configuration name.
+        #
+        # @return [Array<PodTarget>]
+        #
+        def pod_targets
+          target.pod_targets_for_build_configuration(@configuration_name)
+        end
+
         #---------------------------------------------------------------------#
       end
     end