Manually adding GTXiLib and Protobuf-C++

[Farhana Mustafa]

Hey everyone, I'm currently integrating GTXiLIb v4.5.0 into my UITests target. I was originally trying to add the library through Cocoapods but in my Podfile, we're using `use_frameworks!` at the top of the file. Removing this unfortunately breaks other pods we're using (e.g. Realm, RealmSwift)

After a couple of days of not seeing any success with `use_modular_headers!` and `:modular_headers => true` and other hacks, I'm started to manually add in GTXiLib.

Has anyone tried this? I've only used Cocoapods as a dependency manager and having a hard time trying to also add Protobuf-C++ into my project.