The GTM project provides a Framework target and Unit Testing targets, as
well as a CocoaPod.

Unit Testing Targets -

These targets are there to make sure all of GTM is working, and reflect the
hierarchy of the source tree.

Building the "All UnitTests" target will build all of the unittests for the
current configuration included in the GTM package. We require that "All
UnitTests" builds cleanly before we will accept any code submissions.

Framework Target -

These targets are there to make it easy for anyone to quickly add GTM sources
to their own project to start using it or playing around with it. However,
the intent is for a developer to manually add the sources to their project in
the end to reduce the total size of their product (since they only have to
include the parts of GTM they need).

CocoaPods -

The GTM project provides a Podspec for some of the more commonly-used parts of
GTM. See https://cocoapods.org/pods/GoogleToolboxForMac for more info.