CocoaPods post_install step for changing Build Active Architecture Only from Yes to No.

README.md

See CocoaPods arm64 issue for details.

Podfile-snippet

post_install do |installer|
  installer.project.targets.each do |target|
    target.build_configurations.each do |configuration|
      target.build_settings(configuration.name)['ONLY_ACTIVE_ARCH'] = 'NO'
    end
  end
end

I also found this post_install step helpful.

post_install do |installer_representation|
  installer_representation.project.targets.each do |target|
    target.build_configurations.each do |config|
      config.build_settings['ARCHS'] = 'armv7 armv7s'
    end
  end
end

This is an improved version that combines the above two versions and works for Xcode 5.1.1. Based on the (updated) original by Cameron Spickert.

# Remove 64-bit build architecture from all pod targets and override 'Build Active Architecture Only' to NO.
post_install do |installer|
  installer.project.targets.each do |target|
    target.build_configurations.each do |configuration|
      target.build_settings(configuration.name)['VALID_ARCHS'] = '$(ARCHS_STANDARD_32_BIT)'
      target.build_settings(configuration.name)['ONLY_ACTIVE_ARCH'] = 'NO'
    end
  end
end

@dbrisinda Thanks for that version--handy to have both in one!

Updated for more recent: cocoapods 0.39.0 (unsure what other versions it supports).

post_install do |installer|
installer.pods_project.targets.each do |target|
target.build_configurations.each do |configuration|
target.build_settings(configuration.name)['ONLY_ACTIVE_ARCH'] = 'NO'
end
end
end

@nickjbauer Thanks for the update, that works with CocoaPods 1.0 as well.

post_install do |installer|
  installer.pods_project.targets.each do |target|
    target.build_configurations.each do |configuration|
      target.build_settings(configuration.name)['ONLY_ACTIVE_ARCH'] = 'NO'
    end
  end
end