Set xcconfig in App.xcodeproj

lib/cocoapods/installer.rb

@@ -112,19 +112,16 @@ module Pod
       app_project = Xcode::Project.new(projpath)
       return if app_project.files.find { |file| file.path =~ /libPods\.a$/ }
 
-      libfile = app_project.files.new({
-        'explicitFileType' => 'archive.ar',
-        'includeInIndex' => '0',
-        'path' => 'libPods.a',
-        'sourceTree' => 'BUILT_PRODUCTS_DIR'
+      configfile = app_project.files.new({
+        'path' => 'Pods/Pods.xcconfig',
+        'lastKnownFileType' => 'text.xcconfig'
       })
-      lib_buildfile = app_project.build_files.find do |build_file|
-        build_file.file.uuid == libfile.uuid
+      app_project.targets.each do |target|
+        target.buildConfigurationList.buildConfigurations.each do |config|
+          config.baseConfigurationReference = configfile
         end
-      app_project.objects.select_by_class(Xcode::Project::PBXFrameworksBuildPhase).each do |build_phase|
-        build_phase.files << lib_buildfile
       end
-      app_project.main_group.children << libfile.uuid
+      app_project.main_group << configfile
       
       app_project.save_as(projpath)
     end