Why do I get iOS linker errors with my static libraries?
- Open ios/YourAppName.xcodeproj in Xcode
- Right-click on Your App Name in the Project Navigator on the left, and click New File…
- Create a single empty Swift file to the project (make sure that Your App Name target is selected when adding)
- when Xcode asks, press Create Bridging Header and do not remove Swift file then.re-run your build.
This should fix the problem
In my case it was a React-Native project after adding a Swift Pods library. Maybe just the step 2 can work:
- Adding a new Swift file and a Brigde header:
1) File -> New -> File
2) Select Swift File 
3) Confirm Create Bridging Header 
- Go to
Build Settingsand setAlways Embed Swift Standard LibrariestoYES
Apparently for pure objective-c projects you will need to add this $(TOOLCHAIN_DIR)/usr/lib/swift/$(PLATFORM_NAME) to the library search paths of your target. This worked for me when I was including a library written in swift to a project in objective-c