Cannot find <GoogleToolboxForMac/GTMNSData+zlib.h> error when building an ionic project for ios

Question

I came across this error when trying to build an ionic project for ios. It happened in the FirebaseCore build part of the process.

I found the problem was a bug in the following file on line 23:

platforms/ios/Pods/FirebaseCore/Firebase/Core/FIRNetwork.m

It seems the angle brackets don't allow the search for the file to start at the Pods level, whereas quotes allow a relative path to be used.

I found the solution was to do the following, so I thought I'd post it here in case anyone else has the same problem:

Either:

Change line 23 from:

#import <GoogleToolboxForMac/GTMNSData+zlib.h>

to:

#import "../../../GoogleToolboxForMac/Foundation/GTMNSData+zlib.h"

Or:

Add the following to the end of the Header Search Paths setting your Xcode project Build Settings:

"${PODS_ROOT}"