I followed all the instructions on Google Sign-in for iOS using CocoaPods (even though I hadn't used CocoaPods before and still don't really understand what it is) and I am getting this error when I run the program:
'...path/myProject/myProject/myProject-Bridging-Header.h' does not
[!] Unknown command: 'Google/SignIn'
So I solved my own problem and I thought I should put my answer so if anyone has the same problem they don't have to lose sleep over it.
The reason that the bridging header was coming up with an error was because the
Google/SignIn wasn't linked in the Podfile. Instead of following Google's steps in the "Set up your CocoaPod dependencies" section of this page, I followed the steps from CocoaPods Guides - Using CocoaPods to link the pod.
The main step (the one that I don't think happened last time) was this:
Add a CocoaPod by specifying pod '$PODNAME' on a single line inside your target block [of your Podfile].
The last step from here is to...
Open the MyApp.xcworkspace that was created. This should be the file you use everyday to create your app.
so ya... hope that helps somebody