Transitive dependencies on Cocoa Pod

Question

I have an iOS Project with some third party dependencies and some of them are written in Swift. Due to that i have the flag use_frameworks! in my Podfile . The problem occurs when I try to install AppRTC framework. AppRTC has a reference to a static library and pod install fails with the following error:

[!] The 'Pods-X' target has transitive dependencies that include static binaries: (/.../libjingle_peerconnection/libWebRTC.a)

This tutorial explains an approach to overcome this problem by placing a modified version of the podspec file for the pod where the static library resides.

https://blog.sabintsev.com/importing-c-static-libraries-into-a-swift-project-using-cocoapods-a53993c3a2ca#.fo7l8rqxi

I created a custom pospec for AppRTC and set s.vendored_libraries but I couldn't make it work.The pod dependencies of my project look like this. If i install libjingle_peerconnection (where the static library is) and SocketRocket explicitly with cocoa pods, i do not get any error.I a only add AppRTC to my pod file i get the mentioned error.

Question 1) To which project shall i include the custom podspec? Question 2) Do i need to install the pods separately?

               |MyProject|
              /           \
          ....             AppRTC 
                        /         \
          |SocketRocket|          |libjingle_peerconnection|