cocoapods 0.38.2 post_install hook can't update my preprocessor macros?

Question

I added a configuration (adhoc) for my Xcode Project(assume the name is Flurry) and I want to add a GCC_PREPROCESSOR_DEFINITIONS to that configuration like DEBUG.I did that by pro_install hook.I added the following code :

post_install do |installer|
installer.pods_project.targets.each do |target|
    target.build_configurations.each do |config|
        if config.name == "Adhoc"
        config.build_settings['GCC_PREPROCESSOR_DEFINITIONS'] ||= ['$(inherited)']
        config.build_settings['GCC_PREPROCESSOR_DEFINITIONS'] <<  "ADHOC"
        config.build_settings['GCC_PREPROCESSOR_DEFINITIONS'] <<  "ADHOC=1"
        end
    end
end

end

Because I use the cocoapods 0.38.2,So I need to use pods_project instead of project.

The Code works well on the targets that generated by cocoapods,like the AFNetworking, Pods-Flurry and all the third-party frameworks. But it didn't do any change to my project ,Flurry.So the preprocessor marco ADHOC didn't not working when I use the following code:

#ifdef ADHOC
NSLog(@"do something here");
#endif

So , How can I add a preprocessor marco the my adhoc configuration by using post_install hook.

BTW,the code below work on older version,like 0.37.1:

There is only one difference pods_project and project

post_install do |installer|
installer.project.targets.each do |target|
    target.build_configurations.each do |config|
        if config.name == "Adhoc"
        config.build_settings['GCC_PREPROCESSOR_DEFINITIONS'] ||= ['$(inherited)']
        config.build_settings['GCC_PREPROCESSOR_DEFINITIONS'] <<  "ADHOC"
        config.build_settings['GCC_PREPROCESSOR_DEFINITIONS'] <<  "ADHOC=1"
        end
    end
end

end